Hi Thank you for asking HCM I have gone through your query.It is better to decrease or avoid smoking.You should avoid anxiety and stress and go relaxed for sex.You can practice squeeze and stop technique.You can stimulate your partner to maximum before getting yourself stimulated.You can deviate your thought to something nonsexual when you about to near ejaculation.You can put on a condom or condom with anesthetic which will decrease the excessive stimulation on penis and there by prevent premature ejaculation.If all these not helping then you can approach an Urologist or sex therapist or Psychiatrist for behavioral therapy and medicinal management like antidepressants.Hope this may help you. Let me know if you have any further query.