Last time our friend was with us I really watched his balls....weird I know.
He was on his back, wife playing with his dick, one hand at the base of it, other at the top of his scrotum while she was kissing and licking the head.
He's on top, dick inside her, not pumping as they makeout, his balls on her butt almost hit the bed.
He's doing her pretty good from behind, balls swinging up against her belly and back against his own butt.
It's good to share on here, we don't tell anyone we do this....and I sure as hell don't tell my friends I get turned on watching another guy's balls while he's doing my wife...