I haven’t in my adult life (only as a kid), and it was only with 2 other guys (on separate occasions), so technically not a proper “circle jerk”, only a “mutual j/o”. I’d like to though…
I’d like to have one where you’re not jerking yourself, the person next to you is. So a circle of jerking off your neighbor.
As a early teen my friend and I did. He was far more mature and very much more endowed than I was. He loved playing with my little dick and I had super powers when I stroked his monster cock. I think some of our other friends were involved in group sessions while him and I hid the fact we ever went there. I think if the opportunity was presented I’d go there again.