i did this quite a few times from 7th to 10th grade... sometimes even with my own dung!
one time i was out to eat with my friend and his parents at a pretty fancy restaurant. i excused myself to go to the restroom and pinched a little turd off onto the floor and placed a plunger over it. i went back to our table and whispered to my friend to go to the bathroom and look under the plunger. i called that maneuver "the turtle". he later invented a move called "the snail" in which you shit on the ground, take a huge industrial sized roll of toilet paper and smoosh it into the turd sideways, the TP resembles a snail's shell.