Blame it on the Dog
A guy goes to pick up his date for the evening. She's not ready yet, so he has to sit in the living room with her parents.
He has a bad case of gas and really needs to releive some pressure.
Luckly, the family dog jumps up on the couch next to him. He decides that he can let a little fart out and if anyone notices they will think that the dog did it.
He farts, and the woman yells, "Spot, get down from there."
The guy thinks, "Great, they think the dog did it." He releases another fart, and the woman again yells for the dog to get down.
This goes on for a couple more farts. Finally the woman yells, "Dammit Spot, get down before he shits on you."