If you do end up using Vaseline, it will wash out of your shorts just fine. I've used it over last summer and, yes, it wears off as you ride, so you don't have much to clean off yourself at the end. But I also heard what RoadRaven said - petroleum molecules actually draw moisture out of the skin, so it's functioning more as a protective barrier and lubricant against what the chamois can do to you than sealing in whatever natural lubricant your skin has. You'll probably have to plan several "slather" stops on long rides! You poor girl - ouch!!