Mom's accident was three years ago, but her back still hurt. Since she got divorced two years ago, I was her masseur.
It didn't used to bother me. She would lay face down on her bed, with her bra undone. I would sit on her bottom, rubbing her back, up and down. I would rub for fifteen minutes or so, and then I was done.
The first time it happened, her back started having spasms just after I went to bed. So she woke me up. I got up, clad in only my underwear (that's what I slept in during the summer). I sat on her bottom and sleepily started to rub. I got an erection.
As I rubbed up and down, I became acutely aware of my four-inch thingy rubbing against the top of her butt crease. I rubbed up and down a few more times, then, in a squeaky voice said, 'Goodnight!' I jumped up and ran to my room so she wouldn't notice the tent in my underwear.
I lay in bed wondering about the intense feelings spawned by the up and back motion of my erect dick. I recreated those motions with my hand against my underwear, pressing into my hard-on. With a shudder, I came for the first time.
'Well,' came the sound of mom's voice from the doorway, 'I'm glad you took care of that.' Mom had this amused grin on my face. I hid my face under my blankets and drifted off to sleep. That was the last time I went anywhere out of my room in my underwear!
A few nights later, on a Friday night, I was watching TV in my pyjamas. Mom asked me to rub her back again. She lay down on the floor, and pulled her pyjama top up to expose her back. I took my usual position and started to rub.
I was dismayed at my immediate erection. It was as if my dick had discovered that this could be pleasurable and wasn't going to miss the opportunity. I decided to ignore it.
Yet, as I rubbed up and down, working my thumbs into mom's knotted muscles, I was intensely aware of the feeling building in my dick. I then felt mom's butt muscles tighten a few times under me, and I had an even more intense orgasm. I tried to pretend nothing happened and went on rubbing.
The next day, mom brought home this vibrating chair. In a way, I missed giving her backrubs. I certainly could do without the guilty feeling of doing something I shouldn't.