Today, I discovered that I've spent so much time playing Sudoku in the bathroom at work that I've trained myself to need to pee whenever I open the app. FML
Luckily op just said the "need to pee" was there and didn't say "pee." So he opened the app and immediately felt he had to go to the bathroom, as oppose to opening the app and peeing his pants. Either way, I think there's a bit too much sudoku happening, and if you have trained yourself this way, maybe only play it in the bathroom. Pavlov and dog, meet op.
I actually did this. For various reasons I had about a month when shitting was incredibly painful... So I distracted myself with sudoku. Eventually got to the point where, even though i wasn't in pain any more, I found it really hard to shit if I wasn't playing sudoku. It was really surreal...