Ass, arse, butt, behind, rump, heinie, backside, etc. Abbreviation of badonkadonk.
"Dude, you should have seen the bonky on her. It was ginormous."
Something you use when you’re really excited about something and it’s like weirdly exciting.
A booty so phat and juicy it sends you directly to horny jail on sight
The girl over there has such a bonky that my eyes and tongue are about to bug out of my head like a cartoon cat!