Every couple of months my wife and her best friend get together for a girls night.
I usually leave them alone for a few hours so they can do their girl talk and catch up, and then later in the evening I join them for some drinking and maybe cards. My wife knows that as a general rule I will try to shift things to a stripping game at some point, and most of the time she rolls her eyes or even specifically discourages me from steering things in that direction. But every once in a while, I sense an opportunity to go there. The signal I have learned to pick up on is whether the girls ask me to make shots for them. If they do, there is a pretty good chance that the evening will get interesting.
Story 1:
About a year ago, we had one of those opportunities and we started playing a card game and the girls asked me to make some shots. I did so, and we all drank together. Apparently the concoction I created was especially tasty and so they asked me to make another round, which I happily did. After an evening of drinking and a couple shots I suggested that we make the game more interesting, and to my surprise they were both up for it.
There was a lot of joking about the hot-tub incident, and my wife's friend kept insisting that she never does things like this, but she kept playing anyway. Over the next hour we played slowly, see my rules in the first post, the key is to move slow, not put pressure on people and just keep playing. By this time we were all in our underwear and somebody was going to be showing skin after the next hand.
Realizing that either one of them was going to be topless in a couple minutes, or they were going to be looking at my junk, the wife's friend said we should probably do another shot. So I got up and made another round of shots. We all said "cheers" and downed the shots and then sat back down to resume the game. I was in heaven. This is the ENF scenario that I love more than any other. Made even better by the fact that it was just three of us, no dude for me to worry about saying something to kill the mood, and no dude's junk flopping around.