I'm 18 and never had sex before. I had the chance to had sex with a girl a couple days ago. Before sex I was confident and not nervous at all because I've been doing kegel exercises that helps me to control orgasm and last 15-20 minutes masturbating. So I expect to be able to control it the same way in real sex, but as soon as she gives me oral, I completely lost control and cum in 20 secs. I know my hand can't compare to a real girl but from having complete control of 20 mins to 20 seconds is a big jump. Also I had trouble getting it hard again after that which is also weird because by myself I can cum and get it back up again in no time. Anybody have any idea ??
You have nothing to be worried or embarrassed about. Most guys when they first start having sex (be it intercourse or receiving oral) will orgasm very quickly. Remember there is a lot more sexual stimulation physically and visually which you are not use to when masturbating even if you watch porn.
One tip is next time you think you may be getting laid, masturbate to orgasm earlier that day, so there is not build up cum, it reduces the sexual urges and may help you hold out longer before you give her your cum load.
Most importantly just relax and enjoy the pleasure.