my best one must have gone on for about 15 seconds
and the best thing about it was..... i was sitting on the GF at the time, as she was anoying me when i was doing work so decided to fart on her (how imature :P ) but i dident know it was going to be a thunderously loud and smelly fart
she wouldent talk to me for about a hour after HEHE now i just have to say i will fart on you and she run's in the opposite direction