To
shit ones pants. This can be used both literally or figuratively.
To crap
ones self usually due to, but not limited to being startled.
"
Guy chill out, don't
drop your peanuts!"
"Dude I just got attacked by a dog, I nearly dropped my peanuts!"
"I totally just saw this kid yard sale off his bike and drop his peanuts."
"That
baby is a total peanut dropper."