manual plumbing
When you use tissue paper to unblock a blockage in the anal cavity, after you haven't eaten enough fibre and the poo just won't come out, so you help it out a bit.
Guy 1: I just had the worst shit
Guy 2: Why
Guy 1: Had to do a bit of manual plumbing
Guy 2: Why
Guy 1: Had to do a bit of manual plumbing