I am 30 years old unmarried male, with a heavy body type and sitting job. I watch allot of porn and erotic literature, masturbate 4-5 times a week. Now I feel that the frequency is decreasing. Recently I tried to have sex with a willing female friend who is quite experienced, it was my second time (first was not quite appreciable either) I had a decent erection but just before Penetration my penis became soft and lost hardness, I tried twice but both the times same thing happened. This episode has got me very worried. What should I do? Please help.