Funny Joke

So one night a father is up at 5am waiting for his son. The son creeps in the door. The father asks "Where have you been?" The son replies "Well Dad I was out with some friends tonight and you know what I had sex". The father is overcome with delight so he opens a bottle of expensive brandy has a drink with his son smokes a cigar and they both go asleep. Next night the son comes back late his dad eagerly waiting for him. The son steps in the door & his father proud as ever asks him "So son you get lucky again tonight?" The son replies "There's no way I'd be able to have sex tonight my ass is still killing me from the last time".