This bloke was screwing his best friend's wife when he suddenly stopped and sat on the edge of the bed, holding his head in his hands.

"What the hell is your problem?" she asked.
"I feel like a real b***ard, shagging my best friend's *****," the man moaned.

She reached over and patted him on the back.
"Well, if that's all it is, you can stop worrying," she said.
"You're not getting his *****".
.
.
HIS ***** is a few inches deeper."