Fembooty

Combination of the terms femboy and booty .
A fembooty is male butt so voluptuous it makes him appear feminine.

Marc: Damn! Look at her fat ass!
Finlay: Also look at the rest of "her" body. I'm pretty sure that's a trap.
Jamel: He's actually pretty hot. I'd still smash that sexy fembooty.

Ryan booty

A big, juicy, curvaceous bubble booty paired with a small waist
It makes girls jealous, guys sexually confused and pants unable to fit right

It's called a Ryan booty because Ryan has a huge ass