So these 2 guys jump in a taxi cab. After awhile one asked the cab driver, "Do you mind if I pass gas?" The cab driver says, roll the window down and go for it. You hear a faint pisssssss noise. A minute later the other dude says, "I have to pass gas too". The taxi driver says knock yourself out. You hear pisssssssss.
A little further down the road the taxi driver says now I have to pass gas and you a hear this thunderous ROOOOOOOOOOOMP.