Butt-Head: Uh...Yeah, we'll do your wife.
Beavis: N-no! I wanna watch tv. Aah!
Butt-Head: Damn it, beavis, you butt-munch. This guy wants us to score with his wife, and he's gonna pay us.
Butt-Head thinks that Muddy wants them to have sex with his wife rather than kill her and yells at Beavis for wanting to watch TV.