My fondest memories are MFM sessions when my wifey was in her 30s and 40s.

Watched a friend fucking his girlfriend in college while I was "sleeping" on the floor. After a while he got up to use the bathroom down the hall. When he came back I was inside his girlfriend. We took turns on her for a while after that. A good night.

back in my university days a gf sucked my room mates dick, that was hot, visited a few dogging site's

I started going dogging in the 1970s (before it was called dogging!) was a regular at swingers clubs for many years.
I have seen and done it all.... 3 some, gang bangs, orgies and bukkake oh and took 2 diffirent ladies to a very sleazy porn cinema in London on a few occasions....

Similar memories with me too, but in her mid-20ls. Seems so long ago but still very memorable. Watched her many times over about a year.

Watched my wife get fucked a few times, and pre-virus the local porn theater was usually good on a Friday or Saturday night. Awesome to just jerk off openly when people are fucking right in front of you

Watched a young guy service other cocks with blow jobs at the local porn cinema. He just took it all in his stride.

when I was 17, went to a house party with some friends. My best mate took a girl to bedroom and i went outside (it was a bungalow) peeked thru the blinds and came all over the wall watching him fuck her.

I have had other men watch me suck cock in MMM 3some.
I have also watched my wife suck and fuck other men.

I have masturbated watching my cousins fuck each other

Yes we have watched and been watched on nude beach

Have watched wife play and let someone watch us and used to watch a friend in highschool fuck his girlfriend all the time. Wife said she would let her boyfriends friends watch her and him also

Dozens of times -- couples in adult theaters, at swingers clubs, college roommates, wife playing with others. Much rather watch this than porn -- and i like porn!

some college roommate watching way back when. Pre covid I discovered a pretty active adult theater- usually was able to watch several guys jerkoff, some fucking and sucking (mostly m/m, but a little m/f).
It was exciting to spot a couple engaged in sex of some kind and move over next to them and jerkoff while I watched.

I've been watched having sex with my gf at the time. Was at an adult themed hotel with a clothing optional pool. The pool has a huge "play area" mattress with mirrors along the back of it. We were casually swimming and spending time in a hot tub while an older mfm group was hanging out as well. They eventually left and we started getting down to business as we were completely alone. At one point one of the men from the mfm group came in, probably to see if we were still there, and instead of leaving he stayed and watched until the end. He politely remained well off out of the way, said nothing and just watched. It was a serious thrill.