Hello there.  I can understand your concern.  You seem to be suffering from premature ejaculation. You need proper technique. Indulge in a lot of foreplay before actual penetration. And then when you do come to penetration, do the start stop method. i.e., the moment you feel you are about to ejaculate, stop for a few seconds and then start over again. Also pelvic floor muscle strengthening exercises will help you.  Avoid smoking and alcohol.  Best regards. Dr. Anil kumar jain. Bangalore.