I just let loose a warning fart,
To warn you of my morning fart,
It will not be a boring fart,
For all night I've been storing fart.
A fart that precedes a bowel movement. It smells horrible and gives you a clue that a stinky turd is soon to follow.
One guy: "Aww jeez, who stunk up the room?!".
The other guy: "Uh oh, I think that was a WARNING FART", with a look of panic on his face as he runs off to the can to take a massive dump.