I was 125 pounds at 6 feet for decades, kept waiting to "beef up" as I was told I would. Tried everything, hGh and testosterone, working out, nothing worked. Then at 47 (last year) I suddenly went to 160, still slim by most standards (also shrunk and inch).
It was really hard to find clothes, especially since America has gotten so fat, go into ANY store and try to find 28-30 inch waist pants in the men's department. I was having to buy a size 16 from the boys department and there was NO room in them for my dick and the pockets were for kids hands. They were much cheaper though.
I agree about the dick looking proportionally larger on a small framed man. I have a better than average dick, but of the 400+ guys I have been with, and the thousands I saw as a nurse, I would say at least a third were larger one way or another. To look at my photos though people think I am MUCH larger than I am.
The really shitty thing about being rail thin is just how freely people take out their anger and vent frustration upon you because they CAN and get away with it. I have not been to the beach in 10 years because I just decided things would never change, and I have never been to the beach without some jerk (or jerkette) ruining my day with malicious gratuitous comments. If only they knew that bad as they have hurt me they hurt themselves worse.
Can you imagine walking up to a total stranger at the beach and saying something like "why don't you lose some wieght you pig?" Or, "wanna quit ruining the view for the rest of us?" Or, just hauling off and beating the crap out of someone who never said a word to you? These have happened to me and more. They do not usually do this to someone larger, but have NO compunction about doing it to skinny guys.