Pooped his pants - Idioms by The Free Dictionary
poop (one's) pants (redirected from pooped his pants)
poop (one's) pants
1. Literally, to defecate while still wearing one's pants. I need you to pull over the car right now, or else I'm going to poop my pants!
2. By extension, to be very surprised. When I saw that the magazine had published my letter to the editor, I totally pooped my pants!
References in periodicals archive
It's men in FBI-style vans with MI5 listening equipment and CIA headphones telling some shmuck in the street to go up to the general public and pretend he's pooped his pants
and needs to borrow a banana or his dog will explode.
One more lesson: Remind the kids every five minutes to go to the bathroom--in the bathroom, not in their swimsuits--something that was painfully obvious when my nephew pooped his pants
out of excitement.