Here’s a couple:
A few years ago, when I was working out one morning, a new couple came in. It was a bit unusual, as the early morning crowd changed very rarely, They were a nice addition. The guy was a big burly sort and new what he was doing in the gym. The woman was this tiny little 9.75 of a spinner. I kept my eye on her more or less the rest of my workout.
Later, when I walked out of my shower stall, the guy was standing there in the communal drying area. Hanging from his crotch was a cock that looked, at least to me, to be the size of an egg plant. The first thing that shot through my mind was that tiny little woman. Heck, this thing was practically as big as her waist! They came regularly for about a month, but then never came in again.
On another occassion, I was visiting my brother at college. There was a basketball player that lived on his floor. One time I walked into the shower room and he was in it. His cock was amazing. It was reasonably thick, but hung a good two thirds of the way down his leg. On me that would be 10 or more inches. But he was a lot taller than me. I remember just standing there stunned for a minute. I ended up leaving and taking a shower later.
More recently, a friend of mine told me that a mutual acqaintance had an enormous cock. Some time later, while at a party, she and another girl coaxed this guy to take it out and stroked him up hard. It was ridiculous. I am pretty good with spatial relationships and comparisons. This guy was about the size of a standard aerosol can. The killer was they told me that this woman who was at the party, again a tiny little thing, had dome anal with him. I just can’t imagine something as thick as her forearm could make that trip comfortably.
None of these traumatized me, but I can remember the reactions.