Me and my Niece part 1

I’ve enjoyed watching my two Nieces grow up but I always had a soft spot for the oldest; Belle. She was 18 when all this happened, away at college for the first time. One day she liked one of pics on Instagram and so I decided to DM her and ask her how college was going. She was one of the few girls who did not have a room mate so she said she was lonely. I told her she could talk to me whenever she wanted. I felt immediately bad about offering this because it seemed inappropriate and my wife would find out as well as all the family. But the opposite happened: she started to DM me a lot. Even taking pictures of her outfits for classes that day. I was emboldened by this new secret friendship we had, so I started to compliment her a lot. She liked the attention and said our chats helped her get through lonely times. And then one day it seemed to change for us both when she came home from the gym and decided to face time me. She asked if I was alone. I was, and then the next thing I got was a FaceTime request. I opened it thinking we would just be talking face to face. I should say now; she has a cute face, a small teenaged girl body, and surprisingly large chest for her weight. When I clicked on FaceTime I was surprised to see the camera facing her gym shorts. She was on the couch, home from the gym, and she was rubbing her crotch; right in front of me! I could hear her moan but I couldn’t see her face. I asked her what was she doing, she didn’t answer me and continued to rub her crotch...I sat in amazement. My dick was rock hard but I dared not to open my pants and whip it out. It might be too much. I thought to myself just enjoy this moment. The worst thing I did that day was record her. I knew I would want to jerk off to this later. She continued to rub her crotch furiously u till she gave herself an orgasm. Her crotch was wet. As soon as she was done she hung up. I didn’t here from her until a month later.