I also noticed by my own observation - I noticed in many gay/str8 porn that the smaller the tits on men, the thicker/longer (hung, if you will) compared to big tits. Some men who has this "mark" on their chin, either a straight line or circle represents that they are well endowed, this was my other friend's observation. I noticed that also myself watching some porn, or see some guys in the gym by that comparison. I must say it was an impressive observation.
A guy from Japan told me that he can determine the guy's girth/thickness by looking at his thumbnails - one and the other side by side together can indicate how thick he is. To prove this, he demonstrated by using a napkin and folded it several times to the shape of a thin flat cone like - at the point tip..you measure across the thumbnail...to that length - you rip off the point part...then unfold the napkin...it show you the actual circumference in the middle of the napkin. I admit, I was shocked it was nearly precise and I played this on friends...they were shocked. Most of them said it was close, so jokes arise out of it for fun of it. So like many of you say - nonsense, etc. It might be true, but it all depends on individuals!
I remember one guy at a gay bar who challenged me that he was well endowed but had the smallest hands, way shorter than me. So to make that bet, he took me to the bathroom to show me the actual size, my jaws just dropped - he was 11" long and 7" thick! So obviously I lost the bet, had to get him a drink and got a good fuck that night! ;)
Looks isn't everything - but I sure love surprises! LOL