A wailing fisherman is when a guy literally gets sick and hurls while going down on a girl, usually from drinking too much, but occasionally the vagina itself can be faulted. (Not to be confused with the "whaling fisherman," which is a guy who only likes going down on really huge chicks.)
After he finished those last three shots, Johnny went home and pulled a wailing fisherman on his girl. She left him passed out in his own pile, and he spent the whole next day smelling like stale vag and vom.