Hi Thank you for asking HCM I have gone through your query.It is usual to get ejaculation while sleeping at your age.When the storage of semen is full it is a normal physiologic process to get an ejaculation while sleeping.Those who often masterbate that will be rare.You can do good exercise and have nutritious food to gain weight. For premature ejaculation:You should get rid off anxiety including performance anxiety and stress as those are major offenders in many.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 a psychiatrist for behavioral therapy and medicinal management like antidepressants.SSRIs like Paroxetine or Dapoxetine are usually prescribed drugs for this.Hope this may help you. Let me know if you have any further query.