John says to Bill: "Man, my balls are stingin' today."
Bill replies: "How come, John?"
John explains: "Well me and the Mrs. got it goin' real good last night...you know, slapadapadingdong like, and I swear I had my balls slappin' so fast off her ass that it sounded like we had an entire audience clapping for us!!"

Tim: Zack, is that your exgirlfriend?
Zack: No, she's an expotential. We never actually dated...