Inspired by http://doujindo.net/3793.html
Each line is supposed to be one illustration.
I'm thinking more of a picture book layout with text than comic panel.
Double image with motion lines to show cyclic movement. 

Alta: "Oneesan. P-Please stop doing this...."

Danja: "What nonsense. It's your punishment. There's no way I'll stop this. You're disgusting. Having sex with you little sister."

Alta: "Your wrong...."

Danja: "I don't need your excuses, your repulsing me!! Just thinking about you having sex gives me the creeps and of all the people to have sex with.... You chose Mana.... This is unforgivable...! Y-Your tainted libido by this filthy penis is the one to blame, right? You know what? I'll squeeze it so much that you'd never think about Mana ever again...!"
Danja: "Come on, hurry up and leak your nasty liquid from this hole!" as she teases his urethera with a toe-claw.

Alta: "Please don't dig down on my u-re-thra"

Danja "What is this...? Even though you're a boy, you can't stop rattling and babbling on to mm. But I gotta say... For someone who's rattling, you have quite the boner, you're very perverted aren't you?"

Alta: "The base... So tight..."

Danja: "It's because your penis is soaking wet with your precum! It's called incontinence, so I prevented that by tightening on the base of your penis. You should be grateful!!"

Alta: "Oneesan... STop! I-if you keep on.... rubbing me.... so harshly... with your paws.... I'll...!"

Danja: "Otouto... You look funny. <3 A pig like you being with a girl like Mana is a serious sin!! I'll make you understand that and on top of that, you're beginning to squeal like a pig...."

Alta: "Oneesan... I'm Cumming!"

Danja: "Fine  then cum! Let your dirty semen out all over my feet!"

Alta: "Come on now...."

Danja: "What are you doing airhead? It's all your fault that my feet become this dirty. Take my kick into your ballsack and cum all the remaining semen you've got!"

Danja: "Now, learn your lesson and never look at Mana sexually again..."
Danja: "how about to have sex with a real woman?" and starts to pull down her skirt.

Alta: "Oneesan! you're my sister"

Danja: "Isn't Mana your little sister too?"

Alta: "Yes.... But that's different.... We've always been there for each other....."

Danja: "Now you can be there for you big sister too."
Danja moves over Alta's legs, pinning them between her own as she takes his semi erect length in one hand and plays with it.

Alta says, "Danja!" as his Oneesan holds his cock in her fingertips and strokes. Twisting around his girth she shifts her fingertips to feel all the papillae of his length, making grow firmer and firmer as she gives them little tugs.

Danja grins down at Alta, purring, "That's a good boy," 
as she takes his renewed erection in her hand, pressing her palm against his length and fondling his sheath-sax with her fingers.  
She kisses his passionately, first rubbing her lips over his with a slight nuzzle 
then forcing his lips apart his hers and thrusts her tongue into his parted mouth.  
Giving his balls a playful squeeze before moving her fingers up his length and 
wrapping them around his erection she strokes him vigorously until 
he is purroaring deeply and struggling under her.

Danja moves up father, keeping the kiss going until her muzzle has moved to far away from his lips and the kiss breaks.
She nuzzles along the bridge of his muzzle then
the top of his head, finally lets his erection slip from her grip.
Slowing down for a moment to nuzzle over his ear and whisperer gently into them, "My sweet little brother, you're ready to please your Oneesan aren't you?"

Alta nods, his erection raising up parallel to Danja thighs that it is between, his tip close enough that Danja can feel his warmth radiating against her nether lips. "Yes Oneesan."

Danja presses her chest against Alta, burying his face in her cleavage as she wraps her arms around his head.
She lowers herself on top him, nestling his glans between her neither lips.
Having taken her Otouto completely inside herself Danja pauses, letting Alta savor the warm moist snugness of her womanhood.
Danja runs her fingers through Alta's head fur as she rocks her pelvis against him.

Alta lifts his chin back as his length pulses inside his Oneesan, 
spurting his hot liquid essence into her womb.

Danja throws back her head and moans out loud.

His seed over flows Danja's sex and flows down her inner thighs.
Alta's fountain of tiger juice dies down with his orgasm and Danja collapses on top of the smaller tiger boy, still holding his head in her arms.

Danja rolls off of her little brother and Alta takes advantage of their momentum to move on top of her, his legs still between hers.

Alta shifts his position, knelling with Danja's waist between his thighs, the tip of his semi-erection still poking through her labia.

Danja: "You still have more to give your Oneesan?" 
She smiles as she purrs, "Why you are an <i>Amour</i> tiger aren't you?"

Alta nods.
He sits up and takes his big sister's breasts in his forepaws. 
Alta brushes the fur away from Danja's nipples then takes them between thumb and forefinger, massaging them with his finger-pads.

Danja squirms in pleasure beneath him.

Alta throws his head back and lets out a loud deep roar.

Alta makes a mess of their juices on their crotches, their fur soak to mid thigh.
 
Danja: "Oh! Hsingai"

Alta continues to make love to his Oneesan for tens of minutes.
Alta finally runs out of stamina and tiger seed. He lays ontop on Danja, turning his head to the side and pressing his cheek against one of her breasts. Danja laying limp with an Ahegao face.

Danja slowly recovers and wraps her arms around him, rubbing his back with her hands.

Danja: "See I know you could do it Otouto."