This is just funny, I guess. We were doing it, and all of the sudden she starts laughing...so I stop and ask what she's laughing at...she tells me that she can feel my balls slapping her ass! HAHAHAHA.
I have a couple for best.
"His dick is so fucking big."
My wife while I watched her getting fucked.
"That's right you littledick faggot, suck your wife's cum off of my dick."
Same dude, same night.
I remember on the old Hollywood Squares TV show Paul Lynde's answer to "what are two things you should never do in bed," and he said, "Point and laugh."
"You know, I never used to think I was a screamer, but I guess maybe I am."
"OMG, what did you just do to me?" Me: "Um, I just ate your pussy. Surely you've had your pussy eaten before?" She [gasping, whispering]: "Not like that!"
"I always thought I just didn't have a g-spot ... but I do, I do, I really, really do!"
Worst (different women):
Me: "You're so much wetter than you've been in such a long time!" She: "I'm just so turned on tonight." [Yeah, right!]
She (after I fucked her to a fine orgasm on a night when her ex-boyfriend was in town visiting): "Sorry, Jon!" [Hint: my name is not Jon.]