I know this has made the rounds somewhat, but it’s new to me:
From an HBO fight on Oct. 4, someone named Trenton Titsworth kisses his opponent, named Jesse Vargas, and then gets KO’d to the canvas. Video after the jump.
Despite the knockdown, Titsworth was actually docked two points by the ref for nibbling on Vargas’ neck.
You can find a full account of the amorous advance at BOXING SCENE (scroll down).