What is Surprise Pee?
1.
The act of a man whipping it out and peeing at an inappropriate time very near a girlfriend or wife with the expectation of being caught. Can be used to ruin photos others are taking by causing the photo to include the peeing act.
While his girlfriend was watching the fireworks, Jim was able to pull off a surprise pee, which really pissed her off.
OR
It was a special family photo, until it was printed and a surprise pee was discovered.
See