Litmus Piss

The initial test pee after getting into a swimming pool to see if it contains a urine-indicator dye that turns the pool water blue or cloudy, thus indicating the location/catching people peeing in the pool.

Shortly after getting into my boss's pool, I squeezed out a litmus piss to check to see if that bastard added a chemical to the water. Once I was in the clear, I then diluted out the chloride by pissing all over and slowly swimming away.