Definitions by A.A.R.

LSHMDH 

An internet slang term that means Laughing So Hard My Dick Hurts.It was created by a couple of guys while using YIM.

Two people talking on YIM
Guy 1:I just gave this girl a Donkey Punch
Guy 2:LSHMDH

LSHMDH by A.A.R. December 12, 2006