Describe the wildest sex act that you were involved in.

Not sure if you are looking for the wildest act or location. Your question says act, but your examples are all locations. An act is the same no matter where you do it. Maybe you just don't know the difference?

It was a stormy, cold night.
Candles were lit.
I sat there, trousers to my ankles.
Nervous.
At first I hoped it would be gentle.
Instead, it was genital.
My almighty Viking hand grabbed.
It was bliss.

Then I turned off the porn :|

It's taboo.

...I still fell ashame of myself. I was very young.

Women always want to tie me to their bed with silk scarves, spray whip cream on my cock, and suck me off. Pretty conventional, but it's always kind of fun.

I was seeing a girl who had some weird fetishes. One of the things she'd like me to do during intercourse is get up and stand with my full weight on her head.

I once dated a girl who couldn't orgasm unless she was being choked, so I stuffed an orange in her mouth. Did a lot of things that night I'm not proud of, including having sex with her in a cemetery.

I touched a girls "who-ha" with my "bling-blang" it was cray cray

It's a secret.

I had an old college girlfriend who liked to piss on my butt while we were in bed. Wish I hadn't lost track of her. She made walking on the wild side kind of fun.

I was 16 in the late 60's, riding the commuter train into downtown from Chicago's SW suburbs in the wee hours of the mornibg. I was the only passenger in this car, in the upper deck, sitting in front of the window with my pants open and half way down my thighs jerking off to the centerfold in the first Playboy I had ever seen, Linda Moon. I can still see her lovely freckled body today. It was only a side shot showing her large firm tits, the first ones I'd ever seen, but it was a hell of a lot more exciting than the Montgomery Ward and Alden's catalogue pictures of women in bras and panties that I was accustomed to jerking off to. I knew that people at crossings, or in apartment building windows along the way might catch a glimpse of me, and that was exciting too. I knew they didn't know me, and had no way back then to contact authoritiies in time to catch me.

A guy andended up tying my hands up putting a dog collar and lesh on me and pushing over a sofa while pulling on my leash to choke me while smacking my ass at one point he put nipple clamps on me and was pushing my head down making me lick his shoes i love submission and we did other stuff but i think that was the most dirty thing.

I had sex with a married man in his office, we did it frequently in front of a window in the hopes that the guy he was trying to seduce (not his partner) would spot us and be aroused. He found us eventually, called him right up on the cell, and jacked off where we could see him from our window.
No threesome, though.

It's yet to cum. Maybe, I'll share when it does happen, or maybe not.