im 17, me and my girlfriend are sextually active. i have a slight concern about my penis. i tend to get really hard, then after having sex for a while, my penis get unhard. what tend to cause this? and i also have a hard time getting hard at certains time after we're done having sex then we want to go at it again. does a lil rash on the bottom of the penis affects this? because i have a slight one, due to lots of foreplay.
