question: Hi Doctor,  I'm a 16 year old boy (I'm about 1,80 meters and I have no medical history concerning medicins or whatsoever) and recently had sex for the very first time. It felt great, and my girlfriend enjoyed it too, but I didn't have an orgasm and/or ejaculation. After this first time I haven't had an erection just by thinking about sex and before my first time this was very easy. I do masturbate once a day  and I move my penis pretty fast and hard when I masturbate. Also I do smoke 1 maybe 2 cigarettes a day.  Hope you can help me, A normal boy