Oldie but Goodie
Guy walks in to a bar and quickly orders a shot of whiskey and a beer. He slams both back and tells the batender to set him up again. After 4 rounds, the bartender asks, "Whoa fella, slow down. What cha' celebratin?"
The man replies, "Tonight was my first blow job."
"Weeeellll, that is a special occasion. The next round is on the house", says the barkeep.
To which the guys replies, "Naaa, if 4 of those don't get the taste out of my mouth, nothing will."