Well, this is very common in young and older men alike. What you could do is just practice different sexual activities slowly so that you can get used to it. Try not to rush anything. Another thing you could do is masturbate before you and your partner have sex. It usually takes some time for a man to ejaculate after he has came before so this may buy you some time.
Masturbate and ejaculate one hour before you go to your girl friend. It takes little more than half an hour to get the second arousal. This way you may be able to contol your self and avoid premature ejaculation.
Regular practice of deer exercise for man is recommended to increase sexual stamina. kegel exercise and Satkriya also helps to enhance sexual energy.
Hi; you are not stupid practice makes perfect go a bit slower with things and plenty of Foreplay Chill lol...Take Care ............Bob