No, keep the rice dry or it’ll go mouldy after one use :)
Better to go down the drugstore and buy a microwaveable hot/cold gel pack large enough to wrap around your penis. The larger they are, the longer they hold heat. They only cost a few bucks and work well - and you can put them on over a damp cloth so you get the benefit of moist heat penetrating. They hold enough heat for a decent session of PE.
Thank you firegoat. That is a valid point and stupidity on my behalf for not thinking of that. I am thinking of the bead type ones that you can put in a bowl in the fridge and it will absorb the water and be cold for hot days or in a bowl of water in the microwave for heat to calm muscle aches down around the neck and shoulders especially. Although they would not do much good being tubular. I will give your method a shot.