I'm trying to think of a good scenario for Tracer. Considering she's british, I was thinking maybe she could be using a squat toilet on Hanamura (The map from the game that's set in Japan) and it's her first time using one, she could even have a little "accident" such as her pee missing the toilet or maybe even her poop missing because she isn't squatting forward enough.

Then she could act all embarrassed about it or something. Hopefully it turns out well haha :3