Basin Weasel Share definition Flag Poop that lays on the side of the toilet that is not easily drawn down when flushed. Did you see that basin weasel in there? I tried peeing on it and flushing it and it’s still there. Basin Weasel by Hamdog420 August 25, 2021 0 0 Get merch Get the Basin Weasel mug. Buy Now — $32.95 See more merch