Was a few years since it happened but still brings a joy to my face thinking about it.
My mom had a habit of just barging into my room with important news. One evening when I was around 18 I was laying in bed watching a BLUE movie (very mild porn). As I was getting aroused and being nude I had sort of started playing with myself under the blanket.
Suddenly Mom just barged in with some story about a neighbour that was on the late News. Seeing I was not watching the news she was about to turn and leave but then saw what I was watching.
She had on a short robe over the T shirt nighty and when she sat on the bed the robe opened up showing a bit more than just her legs.
She asked if I was enjoying the movie, and before I could say a word she said 'By The Size of That (pointing at my erection) I think you are'.
I mumbled something, to which she replied 'It's ok, go ahead and finish'.
I said no, it's ok, at which she grabbed it through the blanket and started stroking me off, after a minute or so she stopped pulled the blanket down and wrapped her hand around it and started stroking again.
'Much better this way', she said as she smiled at me.
I said 'Mom I am going to have an accident if you keep that up', she replied 'I do not plan accidents'.
I was getting real near the point of no return and she stopped and let go of my penis.
She stood up, pulled off her tshirt and sort of kneeled down, took it in her hand and started stroking again, and as I shot off she pointed it at her breasts.
I shot a few good sized gobs and it was on her breasts.
She stroked me a few more times then stood up with my cum on her breasts and tummy.
I lay there looking at her as she ran her fingers over her panties, smiled, picked up her tshirt and headed out the door. A few minutes later I heard her moaning from her room, then later the shower turning on.
This was the first of three occasions that Mom Lent a Hand.