This just happened last night with my girlfriend.
It was the end of a week in chastity, I was craving touch and I wanted to cum so bad. We were laying on the bed and I started to rub the head of my dick through the little slit.
For a while she watched me rubbing myself, I was starting to breathe heavily and could feel vibrations running through my body. She cuddled up beside me and brought her hand up to my nipple. My nipples have always felt amazing rubbed and she knows that. I was still inside of my cage at this point, but straining to get out. I wanted to feel her hands rub my cock just like they rubbed my nipples.
I wanted to cum in my cage so bad. I just kept rubbing as she brought her second hand up and grabbed my other nipple. So with her mouth now sucking on one, her hand playing with the other, and my fingers still rubbing the head of my caged cock, I started shaking and convulsing. I was in absolute ecstasy and even now the next morning I can feel the muscles in my belly and my ass sore from flexing so much. I didn’t get any cum out past just a little drooling :(