I play with a couple of people besides my SO, but the last time not counting those, was when my wife's friend came to visit us for a few days several years ago.
We have a couple of guest bedrooms, and each has its own bath. My wife is a late sleeper, and I'm usually up by myself in the early morning hours. Her friend txted me while I was sipping coffee and asked me to bring her a towel, which my wife apparently forgot to put back into place before she arrived.
I txted her from the door that I was outside with it, and I'd just hang it on the door handle, to which she replied to just bring it on in. I didn't give it a second thought, as I figured she was brushing her teeth and still dressed. Nope... completely nude standing in the glass walk-in shower. No attempt to hide or cover at all.
I walked into to her bedroom to the bathroom and handed her the clean towel. I figured if she was not going to be modest, I would look
Without paying me much attention me checking her out, she asked if she could borrow a razor, too, which I was happy to go and get her. I didn't knock when I came back this time and just let myself in, and she was still in the walk-in shower preparing to shave.
Maybe this makes me extra perverted, but I loaned her the razor I use to tidy myself up (new blade). From what I could tell, she knew how to put a razor to get use
Throughout her stay, I got long up-short looks almost every morning as we hung out and drank coffee in our sleepwear. Nothing has ever happened between us, but I get the feeling if my wife asked her to join us, she would.