Marbled pussy
BDSM idea by Magnuz Binder.
The glass marbles slide around inside the rubber in your vagina as I push a finger into your orifice. You moan as the smooth spheres massage your inner walls, the pressure building in some places and easing in others as they shift around. My thumb on your clit helps to make your own muscles add to the massage as they squeeze the marbles tight, easing off and squeezing again, over and over.