Funny Joke

This dudes walks into a bar and over the next couple of hours proceeds to get increasingly drunk. Suddenly he spots a guy in the corner with a group of friends and begins to verbally abuse him. "Aye you!" he shouts ."I've shagged your mom!!" The man carries on drinking trying to ignore the guy's drunken rantings. Half an hour later the drunk stands up and renews his abuse. "Aye you!" he shouts even louder this time "I shagged your mom up the ass!" The guy in the corner turns his back on him and continues talking with his friends although by now visibly irate. Half a hour later the drunk pipes up once again. "Aye you, your mom sucked my dick!!" By now the guy in the corner has lost his cool, he stands up furiously and retorts, "For god sake Dad go home, you're embarassing me!"