I was in Vegas a few years ago and if you have never been...go.

Having a non American accent mean that people in bars want to talk to you and comes in handy for starting a conversation with anyone there.
I got talking to a married couple at the bar in the Mirage Hotel.
The chat got smutty and I was at my cheeky best, so when the wife went to the loo, the hubby asked if I was interested in playing some games with them.
When she returned there was a nod and wink between them and I noticed that hubby moved down the bar a little further away.
The wife and I flirted like mad and even the barman knew what was going on, this kind of added to the excitement for me.
Later on nature call and I went for a pee with hubby following behind me. There was a bit of small chat on the way to the loo but when we were both standing at urinals, it was all looking straight ahead as men do.
He started talking to me about how he loved seeing his (hot) wife flirting so much with me and this was starting to firm things up a bit down below.
His tone of voice changed and he almost immediately became quite submissive in his voice. He told me he wanted to see me back in their room and I could do whatever I wanted too, he didn't mind...but
"can I see you cock please? I won't touch it I just want to see it..."
I had finished and with lots of whisky fueled confidence, I stood back leaving my cock out, but it was swelling up from everything I was hearing and feeling.
I tucked it back in and went back to the bar. I whispered into the wife's ear what happened and asked what did she think about me showing off my cock to hubby...
She liked the idea and gave me a little squeeze on the trouser front.
After 10 minutes of her sitting on the bar stool and me subtlety as possible rubbing my zipper region on her bum and right thigh we made our way to the room, my hand on her lovely round bottom, showing off to hubby who stayed at the bar watching us move off.
We played and touched a bit in the lift as much we dare and once in their room we got nice and naked and naughty.
I don't know how much later when the husband came in the room, maybe 15-20 minutes but the wife and I were in doggy position with her face down in the bed, bum between my hands.

I did wonder for a moment if I was about to have the shit beaten out of me, hog tied and butt-fucked like the scene out of Pulp Fiction. Thankfully, he glided past us and sat in the chair in the corner of the room.
Hot wife and I carried on as tipsy horny nude adults do, moving around on the bed, laughing, standing up, bending over and occasionally talking to pants off husband sitting in the corner chair.
We ended up in a wonderful 3sum that lasted hours, involved time in the bed and the spa bath.