Man... it used to happen with me a lot, when i started smoking... i would be SURE that i just had pissed myself... i even had to touch my pants to verify if they were wet... it was bad indeed, but after some time i got fed up with this and decided that i wouldnt pay any attention to it anymore.
So, whenever i felt this unconfortable feeling i just thought "its only your imagination", and it worked. It took some time until i stop feeling that, but since i started to say it was just my imagination i never got bothered when i got this strange sensation anymore.

BTW, its is not a so unusual sensation when one is high... i remember an old thread about this same subject... i did a quick search but couldnt find it. Anyway, i remember that several members reported feeling this same thing.