Older woman wank in the school toilet

I was lucky enough when younger to be at a boarding school, in the middle of nowhere. Now the school was mixed in the sixth form, and that is when I joined. So there were lots of girls around and lots of female teachers too.
In the house where I boarded was a really nice looking MILF – although back then the term MILF wasn’t formed – who managed the house. She was in her late 30s and always seemed to be wearing classic English lady clothes, such as a skirt, tights or stockings (from what we could see) a blouse and jacket. Her titties were always hidden but she showed some cleavage, and with her hair up (blonde hair) she always looked good.
She had an office that had its back to the male toilets – so with a certain angle you could always see the back of her and the back of her legs. I tried to find 15 minutes on most days to go into the cubicles, with perhaps a porn-mag, and jerk off. I must have wasted gallons of spunk there, jerking away to those legs, ass and the profile of her head.
This was fine, and for a sixteen year old boy and I got more and more bold. I used to keep wanking off as she walked around and often I thought she had seen me and showed more and more flesh.
One day the best, or perhaps worst thing happened. She saw me, looked me in the eye and asked what I was doing. In a panic I pulled up my trousers, somehow got my boner inside my boxers and got out of there. It took a few days before I got the courage to go back to the cubicle to have another wank. However, there was no one there….panic. Suddenly there was a knock at the door and the lady was stood there demanding to come in. Shit, what to do. As there was no other exit I had no choice but to let her in.
She asked what I did everyday in the cubicle. There was not a lot to say, as I had a porn mag next to me. She asked if that was really what I did each day – wank over the magazine and over her. What could I say, what could I do. There was no denying it, so I told her that this was what I loved to do.
She told me to wank in front of her – and if I refused then she would go to the house master. So I got my cock out while she stood there and I started pulling myself off. She smiled, opened her legs slightly and slipped one hand inside her panties, past her stockings and suspenders. Her I was, in the toilet, with a lady more than twice my age, wanking while she fingered her cunt. She used her right hand inside those classic white-cotton panties and I couldn’t see her cunt I knew what she was doing. She picked up the porn magazine – it was quite tame but the women inside were stunning – and she asked what I had ever done sexually. I told her nothing – except wank as I was doing then.
There was not a lot of time – we had maybe 5 minutes, so I knew I had to cum quickly. She was focussed on my cock and blur of my hand, and I was only focussed on what I could see – her hairy cunt. I told her I was going to cum – she slid all the way down her panties and gave them to me – telling me to cum in them. So I did, and she also let a small squeal out as she rubbed herself to orgasm. She took her cum-filled panties back and put them in her hand, pulled down her skirt and let herself out of the cubicle. I quickly tidied up, hid the porn magazine away and went back to class.
This never happened again and she didn’t last much longer there. But each day, when I did go back, I know she knew I was there and it took even less time to cum – remembering how her pussy looked and how I spunked inside those panties of hers.