The wildest thing I've ever seen was during a foursome my girlfriend and I had with a married couple. During the sex we swapped partners and the other guy was fucking my girlfriend. My girlfriend is pretty hot and the guy was loving it. I had already fucked his wife so his wife and I were just watching those two fuck.

The guy fucked my girl pretty good before cumming in her pussy. After he came, he laid on my girl for a few minutes. His wife was staring intently at him. When he finally pulled out and rolled off of her his wife slipped between my girl's legs pushing them open. She stared at my girl's pussy, looked up at her and said "sorry, but his cum belongs to me" and started licking my girl's c**t. She lapped up all of her husband's cum as it leaked from my girl's hole.

Afterward my gf and I were like wtf. I've been involved in a lot of crazy sexual stuff but that was pretty weird.