Embarrassing Fashion Faux Pas or ** Mishap?

I was hanging out with a friend the other day, playing video games and shooting the **. She had just flown in to see everyone in our friend group and was staying with me and my roommates for some good times. On this particular day I woke up and started my laundry, making a point to go commando so I could wash all of my underwear-- not a typical practice of mine but necessary in this case. By afternoon it was just the two of us in the house, and at one point I went to the bathroom then swiftly rejoined the casual festivities.

Now we know each other pretty well, but I noticed that during the following 2 hours our conversation was kind of stilted, and she spent an unusual amount of time on her phone. Several times I looked over to her to make a comment or something, only to catch her looking at me already. I was pretty engrossed in the game we were playing (we were passing the controller off) so at the time I didn't think much of it. After drinking a lot of water and eating leftover pizza, I got up to go to the bathroom again, only to realize upon glancing at the mirror that my fly was down. She hadn't said anything to me, so I just assumed that it wasn't very noticeable, despite being down for around 2 hours. When I returned we both acted casual as if nothing happened and the rest of the day went by without further incident.

But the memories of our awkward conversation, her suspicious phone usage, and most of all her lingering glances made me a little paranoid. When I had the house to myself again, I reenacted the scene and discovered to my horror that its likely I partly or fully exposed my flaccid **. For one reason or another though she said nothing to alert me, and I suspect she took pictures or video with her phone while I was oblivious. I can't help but wonder if she was aroused by the sight, staying silent so as not to ruin her show, or was disgusted and petrified, hiding in her phone to avert her gaze. I'm not particularly attracted to her, but knowing the reason really matters to me and I feel like the two of us entered an unspoken agreement to never mention the indecent exposure again. I'd love to hear a woman's take on the matter and put my wondering mind to rest.