Tommy was shopping with his mom at the local 7-11 and happened to glance at the cover of Club Magazine showing a bare-breasted woman and discovered his first "Chubby Bunny."
When someone, usually a male, attempts to fit a female's entire breast in their mouth. Though this act can be sexual in nature, it is much better suited as a display of pure curiosity and willpower to those around.
I haven't been invited over to Francesca's place ever since I failed a Chubby Bunny and spewed half-digested pizza all over her half-naked torso.
A nice, but fat, no very attractive guy who manages to get hot girlfriends and over time the girlfriend also becomes fat and no longer as hot as she was. A threat to good looks everywhere.