My girlfriend was sitting on my lap the other day for hours.. i kept getting erections on and off, but really it seemed like no big deal .. Also since she was sitting on my lap there was alot of pressure being put on my penis... Now I cannot seem to get hard at all and I am wondering if I have damaged my penis, and how I could possibly fix it.
Most likely you can't get an erection because you are worried about not getting an erection. If one head's doing all the work, the other head's not working. Her sitting on your lap's no big deal. If you get an erection with jeans on it's going to restrict your penis in a similar manner anyway. At most you might feel a little sore. Chances are you're getting erections at night when you can't over-think it anyway. Calm down, relax, don't worry, and you'll be fine. Doctor's orders.
worrying isn't going to help you get a erection. you have to let the moment take you over and not worry about it to keep it. once you start to get nervous it's gone.