Its when girls have tits that look big, but they are just chub, not real tits.
Dude 1: DAYUM That girl over there has some HUGE cans.
Dude 2: Dont trip bro, they are only chitties.
Chin titties. When someone has so many layers to their butt chin that they appear to have a pair of breasts coming out of their lower face region.
I'm not sure if I should be turned on or grossed out by your floppy chitties.