A US man has sued BMW after claiming a ride on one of its motorbikes gave him a permanent erection.Californian Henry Wolf claims a four-hour trip on his BMW bike with a 'ridge-like seat' left him with a two-year erection.His lawsuit says he "now is unable to engage in sexual activity, which is causing him substantial emotional and mental anguish".Mr Wolf is suing BMW and seatmaker Corbin-Pacific for lost wages, medical expenses, emotional distress and 'general damage'.He puts his situation down to an extreme case of priapism - a condition in which the sufferer has a persistent and usually painful erection.