Bar and Puke Joke

So this man is about to go down to the bar...

...but his wife says: "You're not going to the bar again. Last time you went there you came home with puke all over your shirt!". Husband responds: "Alright, but I really want to meet up with the guys, so I promise, I'm not going to drink anything". The wife's okay with that and lets him go. When the man arrives at the bar he orders a coke with ice. Of course, one of his friends asks him what's wrong, and the man tells him the story. So his friend says: "Look, here's what you're gonna do. You're gonna have a few beers with us, and if you puke over your shirt again, you're gonna go home with a 10$ bill in your hand and tell your wife that some drunk puked on you and gave you the 10$ for the shirt". This seems like a great idea to the man, and he immediately starts off with a pitcher of lager. When the man comes home at 3am his wife's already waiting for him. "You fucking bastard, I knew it! You got drunk again and puked over your shirt!". The man answers: "No no, you got it all wrong. Some drunk puked on me, but look, he gave me 10$ for the shirt!". His wife says: "Well, if that is true, then why are you holding two 10$ bills in your hand?" - "Oh, the other 10$ are from the guy who shit my pants"