This reminded me of one of my ex gfs.....she told me that she buys ...wrangler? jeans because the point where the leg and zipper seams all met created a "nub" and that nub just happned to be placed right on her clit. If she went moved just the right way, she could get herself off.
She told me she LOVED riding the bus because with the hard plastic seats and the vibration of the big diesel engine she could cum in under a minute lol....
Brings new meaning to the term "riding the bus" lol.....