I used to be a teacher (though it was short lived and I am not anymore), and I never had issues. Just remember that when you are at work, that’s work time, and unless you need them for medical reasons, you should try to put this side of you on hold until you get home. There’s nothing inherently wrong with what you’re doing, as long as you’re practical and no when self-restraint is necessary.

Still, like others have said, don’t upload incriminating pictures online (which is something I think everyone with a professional job should be conscious of), and just have a simple excuse ready in the worse case scenario. Just say you have a medical reason and leave it at that. It’s really no one’s business what you wear under your pants, unless you make it their business (which you shouldn’t lol)