Be careful if you ride with guys on BMW's. You don't want to get rear-ended! READ THE BELOW LINK!
http://content.usatoday.com/communities/driveon/post/2012/04/man-sues-bmw-for-persistent-erection-after-bike-ride/1#.T53dkKuLN8E
http://content.usatoday.com/communities/driveon/post/2012/04/man-sues-bmw-for-persistent-erection-after-bike-ride/1#.T53dkKuLN8E