One thing that contributed to my ED was poppers. I was using them very heavy for some time and had the lack of hard on's...
I would also try to have some older men fuck me, and they have a hard enough to get going on, not super stiff, but good enough to get into my open and hungry hole and they want to hit the poppers way too much (I make a point of warning them that my poppers were the strong ones)...next thing you know, they lose the hard on, want me to suck a now limp noodle and still wanting to hit those poppers... I just have them go...
And with the formulation changes on all of the US poppers, they all burn my nose and I've almost completely stopped my popper usage (not even purchasing anymore, others still bring) and I've been getting some decent fuckable hard-ons, if I had an open hole that was ready to fuck, at the time... I was even working a hot younger man's hole open, in a buddies sling, was tired as shit, did not have a cockring on, but that hole was so awesome and all of the sudden, I realized that I had a boner, stood up and plowed that hole for all it was worth, got softer a few mins later and had gone back to working thag hole open. This happened 3 times before it would not do a 4th, got my two nuts after he had taken me to my place and we had played even more, but did not even get to the point of entery again, but fuck yeah, I was enjoying riding that hole and am very sure that the lack of poppers allowed me to do that.
I tell people (tops), use the poppers only when they really need to, like they are getting close to climax and a few other times, but very sparing. They do very good that way...