Slopping Up the Bathroom

My daughter described something to me she calls "slopping up the bathroom."

"You throw stuff on the floor, tissue all over the floor, and stuff in the toilets and put water everywhere so it slops up."

Apparently this friend of hers has slopped up the bathroom at school a few times this year and last.

"Have you ever slopped up the bathroom?" I asked.

"Once."

"Tell me about it."

She replied: "Those chapters in my memory seem to be missing."