Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/
works/8436214.
  Rating:
      Explicit
  Archive Warning:
      Underage
  Category:
      M/M
  Fandom:
      モブサイコ100_|_Mob_Psycho_100
  Relationship:
      Kageyama_Ritsu/Kageyama_"Mob"_Shigeo
  Character:
      Kageyama_"Mob"_Shigeo, Kageyama_Ritsu
  Additional Tags:
      Sibling_Incest, Coming_In_Pants, some_physical_actions_that_precede_the
      coming_in_pants, such_as_rubbing_and_making_out, it's_a_learning
      experience_for_everyone_involved
  Series:
      Part 2 of ritmob_vignettes
  Stats:
      Published: 2016-10-31 Words: 3433
****** ritsu's big gay step ******
by ecdysisteru
Summary
     Ritsu takes the action that comes most naturally to him, and Mob
     follows.
     [A direct sequel to "mob's_big_gay_step," but it can stand alone if
     you really want it to.]
Notes
     if you didn't read mob's big gay step, all you need to know is that
     ritsu and mob have agreed to meet in ritsu's room tonight so that
     ritsu can teach his brother how to kiss, even though he doesn't know
     how to kiss. also ritsu is gay af
     the prose in this fic isn't any better than its predecessor's, but it
     includes some descriptions that are rather more... graphic. and it
     got way long somehow.
     NOTE: includes a brief teru cameo to keep you on your toes
See the end of the work for more notes
Everything Ritsu knows about kissing, he learned from movies and TV. Though
being someone who mostly watches human dramas, he's actually seen quite a lot
of kissing. Still, he's certain there are some INNER WORKINGS of the kissing
process that he cannot understand by observing from the other side of a screen.
So he does a bunch of research and finds out some apparently important pointers
about how to kiss and how to kiss well. Then, even though he's mentally
repeating all the tips and tricks in an attempt to memorize them, he does an
admirable job of appearing calm, cool, and collected at the dinner table.

Mob, meanwhile, is just staring into space at the dinner table, thinking, "I
wonder what Ritsu's gonna show me later... Hopefully I can still go to bed
pretty early and not fall asleep in class again, urgh..." and not even worrying
about the finer details of the subject in which Ritsu offered his tutelage.

After dinner, Ritsu washes his dishes in record time before brushing his teeth
twice, gargling mouthwash, and applying chapstick. Then he sits in his room
moving his mouth in a spreading-out-chapstick way for several minutes, zoning
out in anticipation and getting progressively more worked up by his own
thoughts.

Then he's like (GASP) "I should do some last-minute studying..!" and he pulls
up the websites that were teaching him how to kiss and scans over them rapidly,
urgently, with INTENSE concentration. He'll have this DOWN PAT and Nii-san will
be VERY IMPRESSED with him!!! Meanwhile, Mob is washing his own dishes and then
leisurely dressing in his PJs and doing the usual getting-ready-for-bed things
and brushing his hair for good measure, and he even sets up his futon so it'll
be ready for him when he gets back from Ritsu's room, because he'll definitely
be back from Ritsu's room tonight, won't he?

And so, around 7:30pm, Mob knocks on Ritsu's bedroom door and then walks right
in because that's just how it works between those two, even though actually
Ritsu doesn't bother to knock most of the time. The instant Ritsu hears the
knock, panic hits him like a hot iron weight dropping from his chest to his gut
and splashing up his back as he presses every button on his phone to turn off
the screen (thus hiding the incriminating kiss-related websites he was perusing
until this moment) and flings it across the room just to be safe. The sound of
his phone's impact with the far wall is fortunately covered up by the sound of
Mob opening the door.

Ritsu was kind of sprawled out on his bed (in an attempt to dissipate the heat
of excitement by exposing as much body surface area to the air as possible),
but when Mob opens the door, he scrambles up into seiza position, then pats the
empty half of the bed in front of him.

"I've been waiting for you, Nii-san."

"Oh no, did I take too long? Sorry, I was just doing what I usually do..."

and Ritsu's like 8-) "NO YOU'RE RIGHT ON TIME." and pats the bed in front of
him again but more firmly.

Mob makes a clumsy sideways transition from "standing next to the bed" directly
to "seiza on the bed," then he looks at Ritsu expectantly. Ritsu looks at Mob's
face, then his mouth, then he swallows...

"All right, this is the moment of truth," Ritsu thinks, "This is what you've
been working for...!" and he reaches out to Mob's face, caresses his cheek, and
tilts his chin upward. Except he kinda overdoes it up the upstroke and ends up
squishing the flesh of Mob's chin upward so Mob is left like '3'?

Ritsu manages to shake off the electric pulse of "I fucked it up"-type panic
that just zapped his whole brain at once and recovers by leaning right in for
the smooch even though he isn't as mentally prepared for it as he hoped to be.

They start out with a slow kiss, or rather, a series of slow kisses, much lower
intensity than their living room kiss earlier in the day, and after a little
bit, Ritsu pulls back but stays pretty close to Mob's face.

"See, Nii-san, you should start out gentle like this. And maybe--" he grabs
Mob's right arm and, without much resistance, places it around his waist-- "use
your hands..." Then Ritsu stretches his arms out over Mob's shoulders, his
wrists hanging limp. And Mob is like (Mob face) "Ok."

Ritsu knows his brother well enough not to be discouraged by a bored-looking
expression, though, and in fact, at that moment, Mob brings up his left hand to
touch the side of Ritsu's face, then he smiles.
"Your face is so red, Ritsu."
Ritsu's face gets Much redder.

He sputters a bit, like "It's just, a tiny bit warm in here, so... but
anyway..." He clears his throat a little, then continues. "Ss- (licks lips) so
then... (staring at Mob's lips) Well, it's easier just to show you, so..."
Ritsu leans in and starts the same slow kiss as before, except after a moment,
he tilts his head and does a big lick over the front of Mob's mouth. They both
startle, because Ritsu meant for it to be a small lick but couldn't hold back,
and Mob has not spent a lot of time recognizing the fact that tongues can be
used for kissing. Right now, Mob is thinking, "Wait, that wasn't Ritsu's
lips... That was really warm... Was that... Wait, if that was Ritsu's tongue,
does that mean, just now, that was... a GROWN-UP KISS? A d-d-d-d-dddd-DEEP
KISS???"

No, Mob, that doesn't count as a deep kiss yet.

But he still feels a wave of excitement zing right down to his gut and then
spread lower, and a little lower... but he can't concentrate on where
excitement is zinging to or from, because Ritsu, who is well on his way to
losing it, has decided to hell with it, let's lick Nii-san's mouth right open,
and his efforts are grabbing pretty much all of Mob's available attention.

Mob opens his mouth for Ritsu, but a little too wide, and suddenly he finds
himself licking Ritsu's entire tongue, the sensation of which seems to be
setting his spinal cord on fire from the inside out, and his arm reflexively
curls around Ritsu's waist, pulling him much closer.

Ritsu is trying desperately to remember what he read about tongues in mouths
and how to do it right, but it seems Ritsu is no longer in the lead, as Mob has
taken to licking as much of Ritsu's mouth as he can reach, breathing hard
through his nose onto Ritsu's cheek, and it's all Ritsu can do to just try to
return the favor at this point, because could it be that his brother is
naturally an amazing kisser? Or does it just naturally feel amazing to kiss his
brother?

But Ritsu's leg is starting to fall asleep, having lapsed halfway out of seiza
and halfway into Mob's lap. He tries to pull away so he can reposition himself
but decides it's not worth separating their mouths for a second, so he instead
attempts to wriggle around and get comfy without interrupting. Mob isn't
thinking about much of anything except how Ritsu's mouth is really warm and he
smells really good and his body is really warm too and Ritsu's breathing right
in his face but he doesn't even care; Mob is being pulled along, riding a wave
that Ritsu set in motion, and his whole body is telling him to go with the
flow, although by now he's unwittingly amplifying Ritsu's cues and almost
starting to become the flow, and what this means is that Mob's movements are
directed by Ritsu's movements. Thus, when Ritsu starts wriggling away, Mob
automatically lurches in the same direction, and suddenly Ritsu loses his
balance and falls backward onto the bed, dragging Mob with him, or rather, on
top of him.

Ritsu's "oof" breaks the kiss without permission from either of them, and Mob
realizes he's kind of applying all his body weight to Ritsu, so he scrambles
back into the most natural halfway-better position available to him, and that's
how Mob finds himself straddling Ritsu and bent down over his face.

"Sorry, Ritsu, are you okay?" He looks down at Ritsu, whose face is so red it's
practically steaming, and Ritsu averts his eyes before replying.

"I'm fine, Nii-san, let me just.. catch my breath for a second..." But rather
than focusing on breathing, Ritsu's mind is overflowing with exhilaration and
anxiety and a touch of embarrassment. The truth is, Ritsu has fallen back into
his typical sleeping position, on his own bed, a position in which he has
passed many a night peacefully jerkin' it, often to a certain fantasy, a
certain fantasy which seems to be playing out at this very moment, and as such,
as if by some cruel form of conditioning, Ritsu is currently sporting what can
only be described as the erection of a lifetime. Not only that, but said
erection is in DIRECT CONTACT (minus about 4 layers of fabric) with his
brother's crotch. His brother's long-coveted crotch...!!! So Ritsu is losing
his mind a little more than ever.

Meanwhile, Mob is also breathing heavily, and he makes good use of this breath-
catching break by staring at Ritsu's face some more. He stares at Ritsu's
mouth, which he was just now touching so much with his own mouth, including the
inside of the mouth(!). He tilts his head just a bit, and from this angle, he
can see the shine from a string of drool going down from the side of Ritsu's
mouth and dripping onto the bed. He stares at Ritsu's mouth some more. His lips
are much redder than the rest of his face, slightly parted and slightly wet.
"Like Hanazawa-kun," Mob thinks without thinking, then he catches himself-
- "Wait, how is that like Hanazawa-kun..?" Mob thinks back to the last time he
saw Teru, the last time he looked at his face, and vaguely recalls thinking
that Hanazawa-kun had pretty lips like a girl. In fact he remembers dwelling on
that thought for a while; had he been staring at Hanazawa-kun's lips that whole
time? Come to think of it, he had been looking rather flustered when they said
goodbye that time. Come to come to think of think of it, the Ritsu beneath him
is looking a bit like Hanazawa-kun after all, at least in that respect.

But that's enough breathing and looking and thinking, Mob decides, and he tries
to lean down into a comfortable position to keep kissing, even though Ritsu,
who ought to be instructing him as promised, is still only overheating in tense
silence below him.

"Ritsu," Mob breathes, and he moves his legs to support more of his weight. But
moving legs = moving hips = feeling Ritsu's hips = feeling Ritsu's pelvis =
feeling something very stiff against him, and at the same moment, Ritsu's eyes
fly open and he lets out a squeak, then slams his hand over his mouth.

Ritsu, knowing his hard-on has been sensed, waits and gauges Mob's reaction
before deciding how to act, though he keeps his hand over his mouth, and his
eyes look more afraid than cautious. Mob has finally stopped looking at Ritsu's
face, though, as he now turns to address a presence in Ritsu's pants he had not
yet considered. Studying the bulge, he reaches a hand down without thinking,
then stops himself, because yup, there's no need to feel it out to know for
sure: Ritsu has a boner.

Mob is like (Mob face) "Ritsu, you're hard." and doesn't break eye contact with
Ritsu's pajama pants. Ritsu shrinks downward and lets out a bit of a nervous
laugh from under the hand still covering his mouth; other than that, he
neglects to respond, because he still can't tell what his brother is thinking.
So he watches Mob look at his clothed dick. Dextrous Ritsu experimentally
tenses a muscle and makes his dick twitch. Mob twitches in turn, then looks
back up to Ritsu's face, but Ritsu has since covered his face with both hands,
because what did he even intend to accomplish with that little experiment just
now?!

"Don't be embarrassed, Ritsu," Mob says, and he pulls one of Ritsu's hands away
from his face. "I'm also..." and he places Ritsu's hand gently somewhere that
is not part of Ritsu's body. Ritsu uncovers his face and looks down, finding
that not only is his hand on his brother's crotch, but that his brother has an
absolute boner, and since when?! Was Ritsu too self-conscious about the poking
of his own dick to notice or even think of noticing that there was another
boner within just a few inches (and about 4 layers of fabric) of his very own
boner?! Then Mob curls Ritsu's hand around his dick proper and Ritsu nearly
passes out.

"See?" Mob says in a voice that doesn't seem very worked up at all. "We're the
same."

Now, if you'll remember, Ritsu was well on his way to losing it just from
having Mob straddle him, so at this point, Ritsu has forgotten any morals,
hesitations, worries, risks, or kissing tips and tricks that may have had him
holding back, and he pulls Mob down to practically lay on top of him before
attacking his mouth with his own, eagerly groping the warm bulge in his hand.

Mob wasn't quite expecting this turn of events, as his actions were largely
motivated by a desire to make sure that Ritsu isn't embarrassed about being
hard, because that's a perfectly normal thing that happens to happen sometimes,
and look, it even happens to him, and he brought Ritsu's hand over to confirm
by touch, because the room was awfully dim with only a desk lamp lit on the
other side of the room, plus he thought Ritsu might be reassured to find that
his brother's dick was just like his. Though maybe underneath those generous
thoughts, Mob is also aware that he's never had a boner in front of anyone
before, nor has he ever encountered his brother's boner, and that some may view
it as strange for both of them to be hard while practicing kissing, but it
isn't really weird, it's just useful practice; after all, knowing that kissing
-> boner is information that is sure to come in handy, for taking precautions
against embarrassing unexpected boner situations. And, of course, Mob knows
that touching a penis during an erection feels really good if you do it right;
he learned that from plenty of personal experience, no doubt about it. Surely
Ritsu also knows about that kind of thing by now..? But if the tables are
turning such that Mob has to be the one teaching Ritsu, then so be it-- because
this is something worth knowing.

Of course, Ritsu already knows about that kind of thing, but he's no longer
worried about what Mob is thinking; right now, he's in the mood to let his
brother do whatever he wants. So Mob follows Ritsu's lead in the mouth area,
but at the same time, he reaches down to take their dicks out for some good old
fashioned jerkin' it. Ritsu refuses to let go of his dick, though, and in fact,
he's started moving in a way that feels really good somehow, an unfamiliar
friction between the fabric of pants and the fabric of underwear. Mob starts
second-guessing the idea of taking their dicks out at all, instead starting to
slink his hand up Ritsu's shirt because he figures it might be nice to feel his
little brother's heartbeat while they're doing other things that feel nice.
Observant Ritsu, without breaking their sloppy ongoing kiss, hijacks Mob's
wandering hand and instead directs it to wrap around his own clothed dick. Mob
finds, as a pleasant surprise, that he can feel Ritsu's heartbeat strongly here
as well.

The brothers settle into a good rhythm, the two of them a writhing mass of
sweaty fabric and body and mouth, breathing out in hot puffs, leaving not quite
enough room between them for their hands to perform any proper jerking motions
but making up for it with the almost-coordinated movement of their hips against
each other. Ritsu moans into Mob's mouth, and Mob almost stops to ask if
something's wrong, but his stopping is stopped when Ritsu's non-dick-touching
hand pulls Mob's shoulders toward him, deepening the kiss.

Yes, that counts as a deep kiss, Mob, it's been qualified for a while now.

Mob is slightly taken aback that the almost pained noise from Ritsu was
actually a noise of pleasure, and the shock of the realization sends sparks of
heat flickering straight to his balls. At that moment, timely Ritsu shifts his
grip on his brother's dick so his thumb can travel down to briefly press and
rub his balls, and Mob finds that this time, he's the one being muffled by his
brother's mouth.

Ritsu, having lost absolutely all of his self-restraint and now moved purely by
instinct and impulse, reaches down and cops a good feel of Mob's ass, and at
the same time, he bucks his hips up into a really solid grind. Deciding to go
three for three in the "exciting new stimuli" category, Ritsu also breaks away
from the kiss and starts sucking on the side of Mob's neck. Simple Mob, who was
having a very good time but not expecting Ritsu to act like a lover, is
overstimulated and pushed over the edge in short order, pressing his face into
the pillow next to Ritsu's head and thinking of nothing but sweet Ritsu as he
shamelessly spills it in his PJ pants.

Ritsu is pretty distracted by the newfound pleasures of feeling up his
brother's ass, but his non-ass-occupied hand soon alerts him that the PJ pants
situation has become goopy. In fact, Mob's hand has slackened around Ritsu's
dick while he selfishly humps into Ritsu's hand for a few seconds. Oh shit.
Ritsu understands what is happening, and it's too good to process, but he
manages the gist of it: Nii-san is on top of him, and he's cumming, right now,
into Ritsu's hand, and breathing hotly onto his neck. That thought alone is
enough to make Ritsu completely blow his load even though the hand on his dick
hasn't done anything in the last 20 seconds.

Mob is half-aware that Ritsu started moving a little faster and then stopped
moving except for the rise and fall of his chest, but he's too sleepy to make
anything of it. The two of them lie there panting for a bit. Then Ritsu speaks
up.

"Nii-san, could you roll over next to me? You're a little heavy."

"Ah! Sorry, Ritsu, I wasn't thinking."

As the ritmob sandwich opens, their very soggy crotches are exposed to the air,
which rapidly makes their pajama pants feel unpleasantly cold against their
sensitive junk. And so Ritsu and Mob spend some time deliberating on which
would be more suspicious at this time of night: taking showers or doing
laundry.

They settle on doing a normal load of laundry with their combined clothes and
some linens from Ritsu's bed that got sweated on but not soiled. Having cleaned
themselves up and put on some fresh undies and backup pajamas, Ritsu and Mob
sit together in Ritsu's dim room, on the fresh sheets now covering his bed,
waiting for the noise of the washing machine in the other room to stop.

"Ritsu."

"Yes, Nii-san."

"I had fun tonight. And I feel like I learned a lot."

"Me too, Nii-san."

"But I think..." Mob stares into middle distance, contemplating. Ritsu's heart
pounds in his ears, the chill of worry creeping over him; could it be that his
brother regrets doing the dirty things they did...?! Even though Ritsu is
feeling what must be the opposite of regret...??!

Finally, Mob speaks.

"We should practice some more tomorrow. Because... (now whispering) I know a
way to do the same thing but without getting our pants all sticky."

Ritsu grabs Mob's hands with both of his hands and looks him right in the eye.
"COUNT ME IN."
Then they made out for a while, spooned, and fell asleep without putting the
wash into the dryer, and in the morning their laundry was all musty.
 
[[TO PROBABLY NOT BE CONTINUED... OR NOT SO PROBABLY?!]]
End Notes
     not endorsed by chapstick (c)
     welcome to [No Regrets Ritmob], a subsidiary of [Nothing in the Room
     Starts Psychically Flying Around or Crashing when you Cum Ritmob]
Please drop_by_the_archive_and_comment to let the author know if you enjoyed
their work!