FaceTime is embarrassing

Some time ago I got a phone call which I thought was a regular phone call but was actually a facetime call. It was a little embarrassing for both parties, since it was a wrong number! Today I got a call from the lady in the neighborhood who didn’t even know she was making a FaceTime call and thought it was a regular call. Realizing this, I said, “are we on a video chat?“ She was embarrassed because she did not think she was presentable, but I assured her I could not see her. To make matters worse, she thought she hung up but I could hear her talking about me after the phone call! To be honest, it was not all bad and in fact it was rather interesting, but to avoid further embarrassment for both parties, I thought it best if I hung up before she realized we were still connected. Unfortunately, looking at the phone screen, I could not see a hangup button. I ended up having to do a force restart and losing a project I had been working on. The book I got on the iPhone did not include a section on FaceTime and it is not the most intuitive app. How can I avoid further embarrassments?