1) A completely childish derogatory comment towards another, proclaiming that the individual possesses a scrotum complete with
pubes, hanging from his / her chin.
2) A completely accurate comment towards another, if that person actually does possess a scrotum hanging from his / her chin.
3) A
game played in
prison by your cell mate, when he's not jerking off over pictures of Clysdales or arguing with his imaginary friend Jerome.
George: Fuck, here comes Jon, that balls-on-chin...
Andrew: I thought I smelled something
Doctor: I'm very sorry Mr Buffington, you appear to have a severe case of accute balls-on-chin.
"...And your cellmate makes you play a
game called balls-on-chin...And what happens next is all a blur, but you remember "fist" can be a verb..."