I haven't measured my penis since middle school
Warning: English is not my native language.
When I was in high school (around 15), I went on a trip with my classmates. I was still in the closet as gay, but one night the conversation turned to girls, sex, and masturbation, and I felt the urge to jerk off. I went to the bathroom to "pee"—though I actually went to masturbate—and somehow, it seems they saw me doing it. The next day, they were making comments and jokes about small penises and the shape of mine (it curves quite a bit upward, against my abdomen); they didn't explicitly say it was about me, but it was obvious they were mocking me.
Since then, I haven't measured my penis—just in case it turned out to be small. I know it has changed, and plenty of guys have told me it’s a good size—even big—and that they like the shape, but I prefer not to know the exact size, just in case it disappoints me.
I know size doesn't matter, but when I'm hooking up with someone and they ask how big it is, I prefer to tell the truth and say I haven't measured it.