This dude suspects his gf is cheating on him, but he needs solid proof that she's a banging prostitute. That's why he has her tied and blindfolded and lets his friend seduce her slurping muff to look her reaction when she finds out who's actually screwing her. She makes it watch appreciate she's shocked and unwilling at first, but then her slutty side takes over and she enjoys love with a total unknown person as well as a sloppy jizz appreciate a real hooker.
