Aha, a new vocabulary word --from Викисловарь I think it must be гадить/нагадить, right?
But is it very rude? Would a mother say to a child "Осторожно, не ступай туда, где щенок нагадил на полу?" Or is there a more polite word that one can use around children? (I only know the "clinical" term испражняться and the rude срать.)