One who, while enthusiastically engaging in vaginal sex suffers slippage
and hurriedly rams the offending phallus home into his unsuspecting partner's equally unsuspecting rump.
Hungover Dude #1: Man, last nite when I was givin' the ol' hogleg
to Donna, it slipped out and I just lined 'er back up and rammed it right in her brown ring
Hungover Dude #2: Stevie, that is why you, my friend, are the brown ring king!
(High fives are exchanged and beers are opened)