belly boy

A guy who likes to play with, show off,or grow his belly. It can be sexual and most times is,but not all the time. It can be used interchangeably with gainer.

Do you know why Zach stopped going to the gym, his getting fat

I heard his girlfriend is into belly boys

That explains why he let himself go

belly boy

A belly boy is a guy who has a large belly and finds enjoyment in having it played with, showing it off, or wanting it to grow bigger gainer

Jonny has gotten pretty fat lately
He actually seems to enjoy having a belly

I think he might be turning into a belly boy