Morty smiled and nodded his head, “Y-yeah Rick!”

"Alright, tyke. Hold still while I get you undressed." Rick said as he began to remove Mortys shirt.

Morty smiled, “O-okay! I-I will!”

Rick smiled as he gently removed Mortys shirt, shoes, and pants. This left him in just his briefs and socks. Rick looked at the onesie and then at Morty. "Hmm... I might need to put you in something else before I put you in this onesie." He said.

Morty blushed and tried to cover up, “L-like what Rick?” Morty asked with confusion.

"Well sweetie to make sure this really fits you properly, Grandpa is gonna have to put a nice thick diaper on you." Rick said. He moved Mortys hands away casually. "I've seen you naked before tyke, no need to cover up now." He said.

“W-wait a diaper?!! A-are you sure Rick? T-that seems really… um embarrassing!” Morty stammered with a blush.

"Shhhh it's okay little guy. Grandpa knows what's best for you, don't worry." Rock said. He hugged Morty and kissed his forehead. "Alright little buddy wait here." He said. Using his portal gun, he shot a portal at a wall and walked through it. A few moments later he returned with a plastic changing mat, 5 packs of thick diapers with cute baby designs on them, plenty of wipes and powder, and plastic pants. He set everything down and closed the portal behind him.

“W-wow Rick! W-where did you even get all of that?” Morty asked, trying not to stare at the diapers that would soon replace his underwear.

"There's a planet that has all this stuff, sweetie." Rick said. He laid out the changing mat and gently patted it. The mat had cute planets and was space themed. "Come on little guy, lay down." He said.