He sees a guy at the bar and says “Hey I just had sex with your mum!”

They guy at the bar ignores him and walks away.

A few minutes later the drunk man goes over to the guy again and says, “I had sex with your mum, and it was great!”

Again, the guy ignores him walks away albeit angrily.

A few minutes later the drunk man goes up to the guy and says, “I just had the best sex ever with your mum!”

The guy, who has now had enough says, “Shut up dad! You’re drunk again!”