Hi thanks for contacting HCM .. At such a young age cause for this problem is mainly performance anxiety ... Remove stress related to sex .... Perform it in suitable position .. Fore play has to be done before sex more ... Yoga and daily exercise useful .... To avoid premature ejaculation..... -Double condom can be used . -kegel exercise useful in some case -penile squeeze technique useful -you can apply local anesthetic over glans penis prior to penetration -masturbation before sex useful -deep breathing and focusing exercise useful ... -stop start technique also useful If you are obese loose weight ... Smoking alcohol avoided ... Measure your blood pressure and rule out diabetis ... Consult psychiatrist and discuss this ... If still problem remain than we will do further work up . Take care