Yosh and Nishi were out at a Halloween party together! This year Nishi was dressed as a slice of pizza, and Yosh was dressed as a baby.

"Haha, I can't believe you really did it." Nishi laughed as he put his arm on Yosh's shoulder.
"What? It's a legitimate costume! People dress up like babies!" Yosh defended his party attire.
"They sure do - usually at home in privacy though." Nishi nosed Yosh's blushing cheek. "Is this all from your personal stash?" Nishi pulled on the waist of Yosh's diaper, "These seem like they're exactly your size..." his finger pulled the front of the diaper open a bit.
"No! I don't have a bonnet and an over-sized bottle at home like this." Yosh pointed to the more baby-like items of his costume.
"Yeah, but you can enjoy them full time whenever you want now that you went and bought them, hmmmm?" Nishi kissed on Yosh's beak playfully as he peered down into the front of his pal's diaper. "WOAH there - someone powdered up their baby bits!" Nishi laughed as Yosh urged him to quiet down. "Is the little guy comfy?" Nishi wiggled his eyebrows.
Yosh bit his lip - worrying folks would look, but luckily no one did, as Nishi had a front seat view seeing Yosh's penis, which was looking plump and cozy on his tight little feathery ball, started to come to life, growing and showing his green stripe inside his diaper, the pink tip covered in white powder pressing against the diaper. "Oh gosh..." Yosh almost moaned, the soft touch of his skin against the diaper was quite a lot for him.
"Yosh! You're not quite playing the part." He closed Yosh's diaper and pressed his hand against the bulge in front. "I don't think they're supposed to get turned on by being in diapers like adults do..." 
Yosh looked around nervously - quite aroused from the sensitive sensations below.
Nishi took the bottle of warm milk and-"Wait, warm milk!?" Nishi laughed and felt the bottle, "My gosh. Halloween is really your first day going completely baby out in public like this huh? I'm so proud of you~" the yoshi teased his friend, opening his diaper again and squirting warm milk inside. "Gotta feed the little guy~"
Yosh went wide-eyed as warm fluid spilled into his diaper, and slowly tricked down his erection, and wet his little warm balls. "N-N-Nishi... c-careful..." Yosh started to cover his beak, his poor penis feeling so tense and sensitive in his diaper.
"Let's walk you outside to get you a little fresh air, baby doll~" Nishi put his hands on Yosh's diaper-covered butt, forcing him to walk forward - each step and sway made the ducky dino moan, his penis pushing and sliding around in the sensitive milky powdered situation he had in his diapers.
"Oops!" Nishi accidentally bumped Yosh against his sister Winry's skirt and feathery tail - and again against the back of Macaroni Penguin's head - lots of soft feathery surfaces his penis could slightly feel against the diaper.
Yosh held his head up, gasping, no words, he was on the brink of orgasm.
"Feel the breeze, yoshi baby~" Nishi laughed as the two stepped outside, and Nishi undid the tape in Yosh's diaper - the cold breeze outside tickling his wet, naked, erect penis - the exposure and feeling his soft diaper fall right against his penis made Yosh QUACK out loud as he began to cum! Just as others turned their head to look, Nishi used his hand to push the front of the diaper against his friend's wet erection, snuggling the diaper close to the underside of his little winky as Yosh came and whined, pressing right into the diaper. Nishi hugged close behind Yosh and tried to keep the diaper in place, but after a moment Yosh relaxed, and fell on top of his buddy - his diaper now covered in cum laying on the ground outside.
Nishi cuddled his bottomless buddy on his lap - at least that powder kinda covered him! ...Sort of. Nishi went through Yosh's bag of accessories and helped wipe his winky clean of cum, milk, and powder, before he laid his friend back, spread his legs, and powdered his penis, balls, belly, legs, and butt all in whiteness.
Of course, without another diaper, and Yosh feeling almost drunk with sleepiness, he walked Yosh back inside so the two could leave the party - those who noticed gasped as the saw the sleepy adult baby walking around with his powdered widdle winky wobbling around - with Nishi giggle and fake apologizing for it - before they headed home - Yosh in his bonnet, shirt, bib, footies, and a nice powdered from. The two wound up at Nishi's apartment to sleep the night away - Nishi offering to share his bed with his bottomless pal.
"Hehe, even if I tease... it's really a cute costume." Nishi smiled, kissed Yosh's beak, and groped him below. "Nighty night, little duckling~"