An exclamation. 12:15 is the ultimate argument-ender, however it only works if both "ya face" and "ya mum" have been mentioned in the argument.
exception: Saying 12:15 to someone at exactly a quarter-past noon/midnight grants you instant victory before an argument has even begun.
Bob: "You're stupid!"
Pete: "Your face is stupid!"
Bob: "Your mum is stupid!"
12:15, or 12:15 tits are tits that have nipples facing in different directions
It is referred to as 12:15 because the tits that inspired the term had one nipple that pointed up and one to the side, giving the impression that the nipples were like the little hands from a clock, and if it was a clock, it would read 12:15
Dude: Check out those tits. *Shudders* Those are some deformed ass 12:15's
Bro: Nah one of them is pointing up and the other is pointing down, that technically a 12:30