Hi Tom, Try this, google my hard wear, they sell lots of differant c*ck rings, seeing as you can get a good semi goping you may find that a ring will take you all the way, I have one it works for me and my wife, I got one to boost my erections after ED.
Not to be a *****, but is it possible that maybe you are not so "gay" The times when you have had an erection with a partner maybe were just very highly stimulated or excited because of the act of sex.
You are to young for ED. So maybe you are not that turned on by men. Have you ever been with a woman? If so did it turn out badly, in other words could you perform? You say for 4 years, since you were about 20. What about before the age of 20 or were you a virgin? And of course have you been checked for STD's
I do hope you find an answer to this problem. Good Luck. Let me know how things turn out.