A piece of fecal matter or doodie made in school as opposed to home or some other place, generally it is left in the toilet for other students viewing.
Hey Matt did you see that school doodie
in stall 5 today he could have done his doodie at home.
Marsha did you see all the school doodie in the bathroom today, I have to go earlier in the day or hold my doodie till I get home. I know that girl must have had corn for dinner last night.