A Masochist exits a grocery store one day and immediately collides with a passing Sadist. The sadist apologizes profusely while helping the masochist pick up his scattered groceries.
"I didn't hurt you did I?" quizzed the sadist.
The masochist replies;" Just a little but it's OK. I'm a masochist and I enjoy pain" The sadist eyes his new victim with anticipation while telling the masochist that he's a sadist who enjoys doling out pain. The sadist invites the masochist to his home where he promptly ties the fellow up in a corner.
The masochist notices a display of whips on the wall and asks in a quivering anticipation; "Are you going to beat me with those?"