Unable to maintain erection, Help

Patient: Dear Doctor, I am a 23 year old male who is having problems maintaining an erection during sex. I have no problems when it is oral sex but can not keep one during intercourse. I am a smoker and do drink occasionally. What can I do to help this problem

Doctor: You need to avoid smoking and alcohol to help with this problem. Having a healthy diet and lifestyle would increase your confidence and improve your performance. Meditation, yoga or any kind of daily workouts may also help.