That's perfectly normal. It happens with everyone unfortunately. Even guys will masturbate and then feel like they're getting close only to not, and then feel liek they can't go anymore. It sucks when it happens, but it does happen. The best advice I can give for you? Relax a little bit, and realize...

I don't know if it's a common problem. I'm 16 and I've had sort of the same problem and thought something was wrong with me for a little while. I mean, I'm not as sexually active as I think I'm ready for (I guess all teen boys though), and since I hit puberty I've masturbated quite a lot. But it's o...