One of The hottest thing we have ever done was when we went on vacation in our twenties with another friend couple and shared a room because we were all in college at the time.
In the middle of the night my wife quietly woke us up to our friends quietly fucking. Well this of course got us both hot. It felt naughty being so close to people we knew who were ducking. I started stroking my cock and I went between playing with her nipples to rubbing her clit, trying all the while to be quiet and not let them know we knew they were fucking. Small moans of pleasure kept escaping from their side of the room. After a few minutes of this going on and me getting harder and my wife wetter and my wife whispered in my ear and begged to suck my cock. I wasn’t gonna turn that down so she went under the covers and started sucking me off. It was amazing feeling my cock get swallowed why I tried to see if I could see our friends fucking in the dark. All I could see where their covers and bedding and movement.