when you are having a shit in the toilet and forget you didnt lock the door and your dad walks in whilst you are masturbating and using your own shit as lube and your dad automatically shits himself at what he has just seen.
Tony: i was unlucky yesterday mate
Steve: why what happened?
Tony: I was having a great dirty wank when my dad caught me of guard with an ian-mcbanging-shit-daddy.
Steve: Oh man, unlucky pal but cheer up my dad nearly caught me last week but I managed to wash my dick in time.