Please explain to me, in plain English, how your coworkers and bosses come to know your dick size without you telling them or showing them.
Over time, with things that happen under normal socializing activities, men tend to see or glimpse the penises of their peers.
True, seeing an erect one is very rare. However, rightly or wrongly, estimates are made from flaccid dimensions. At the extremes of size this information is automatically gained when, for example, peeing in the woods, even when not facing each other. Digging it out as opposed to letting it flop out is pretty obvious. For those in the average range, peeing in the woods might not be determinative at all. But, of course, no one makes "average penis jokes." They make "small penis jokes."
I happen to have new living arrangements for about 10 months. 2 men I now associate with frequently for family reasons have seen my penis and I have seen theirs. In both cases because of being at the YMCA with respective families and using the locker room. Another guy might have some awareness from a hiking trip we took with our families. Though not directed at me, I heard 1 guy "joshing" another that "I didn't think it was that cold today" when he noticed him struggling to pee.
It took several months before we actually saw each other at the Y though we were there together routinely. Sure, I could have taken extraordinary step to avoid being seen through all this. However, in my estimation, that would give a worse impression than my small penis itself.
I have been asked this before, I answered though in less detail. People laugh it off as a small penis joke.