I would like to offer my senior advice and some of that from a trans friend I used to go to college with. Guys don't notice and don't care. They go into the bathroom, do their business and leave. You could sit in the stall and play with the Toliet Paper and undo the whole roll and more than likely no one will notice or if they do, they will not commit unless they are very chatty and even then, I doubt they will would care why you did so. (Seriously, go do it and see what happens)
In fact, I think it should be a social experiment for all. Go into the bathroom, waste toliet paper, see if anyone says anything. It will make you feel more comfortable I think with this kind of situation. Oh, but don't use the whole roll, otherwise the guy behind you might be miffed he needs some too.