Caught cock in hand

Growing up in a house full of women, as the youngest and only son and having 2 older sisters living with our grandmother and mother. My father departed when I was 12 and we hadn't heard from him since. I left school at 16 to become a mechanic and still living at grandma's home at 20. My older sisters were going to university and the oldest was in her final year. Both my mother and grandmother worked and worked on every second weekend as well, I was usually off weekends and had the house to myself every second weekend as my sisters were either working or with friends. So, I was home and feeling horny and watching a bit of porn. Not expecting anyone home till late afternoon, I was laying my bed and stroking my cock and my mother 44 walked in and caught me. She had finished early as the power had gone out as a car took out a power pole. Unable to work without power she was sent home. Nothing I could do at the time as I hadn't heard return home, and I had my door closed. But she came to ask what I would like for lunch, thus catching me masturbating. To my great surprise she offered to masturbate herself and what could I say but okay. But masturbating me didn't help her, so we ended up fucking twice. Since then, my mother uses me to satisfy herself and me at the same time. I do date girls and have gotten sex before, but rarely and my mother is a very willing woman. She managed to change her weekend work to her off week and thus being home while my grandmother is working. My grandmother works at a club in reception/bookings and only works days shifts. So, when gran is at work, her daughter and grandson have sex and plenty of it.