Nah, all dudes measure their dicks, gay, and straight alike.
This is how I do it - since I'm an American, I don't use the filthy metric system. I measure my dick with superior units, known as "Arthurs". Arthur is my good childhood friend from elementary school, and he has a very standard size penis. Therefore, it makes sense to use his member as the standard bearer for all other cocks to be measured by. We all do!
Of course, we need to be naked and facing each other to compare his to mine and get a good measurement, and of course, we both have to be erect since flaccid length doesn't count. A little hand cream also goes a long way to ensure accuracy.
I'm about 1.2 Arthurs, if you need to know, which is also, interestingly enough, pretty close the the length of my teeth to the back of my throat, which is 1.3 Arthurs. For reference, the diameter of my grandmother's peach pie is exactly 1.0 Arthur, and one adult hamster is 0.3 Arthur.
Now, if we're talking girth, I'm a little undersized at 0.8 Philip, but that's a whole 'nother ball game.
But yeah, this is straight up math - not gay at all, I dunno what you're on about, OP.