Hi sir/mam I am 23 years old. I am a football player. I have some problem in doing sex. The problem is whenever I try to do sex I loose my penis erection. At the age of 18 I started playing football frm then I used to do less masturbation as advised by my team mate. Before I used to do masturbation 3-4 times a week then after only once a week nd slowly slowly once a month. 19 was the age first time I tried to do sex tht was the day I hadn't got the full erection of my penis I don't know the reason whether I was scared or not or something else .Then after I tried to do sex after 2 years I was 22 years thn again same thing happened I haven't got erection. Nd now few days before I tried to do sex with my girlfriend same thing was happening I got erection for some time doing oral sex bt it was not tht strong. I struggled for whole night then in the morning I used viagra then only I got full perfect erection. So please help me. Thanks in advance.