1) Remove lid from toilet
2) Flush toilet, then grab black floating ball in the tank before the bowl refills. Hold the ball there for now. The bowl of the toilet should be empty.
3) Fill the bowl up with vinegar
4) Pour about 5 boxes or baking soda into the tank
5) Release black ball, so the baking soda mixes with fresh water, and replace the lid. - leave, watch, and wait.
When the next user of the toilet takes a shit, the vinegar and baking soda mix to make what can only be described as a shit volcano.
Girl: I just got done doing an Old Faithful.
Guy: What the fuck?
Girl: Yeah, I do it EVERY time I masturbate.
Also, a CoRec Ultimate team at UC Berkeley.
Stranded on a desert island, Gerry had to resort to an Old Faithful to fill his facial quota.