While you're driving to/from college, wear trousers pantyless. As you get into the car, unzip your trousers and apply a clothespin at each inner lip, then start and keep them there as long as you can (anyway no more than 15 minutes to avoid damages), then stop the car (safety overall) and strip away the clothespins.
If you use
this kind of clothespins you could experiment gluing something between the sticks, near the spring, so that the sticks don't close completely but remain a couple of mm opened, so it will be less painful and blood-blocking, and they could be applied for a longer time, but making it more uncomfortable.