Rather than putting a vibrating cock ring directly on my cock, I find I can delay orgasm for hours with the following technique:
I got a plain, stretchable cock ring that can be stretched around my cock. I attach a wire (or string) to the cock ring and attach the other end to a vibrating egg. I slip the stretchable cock ring around the head of my cock to where it is touching the underside of my cock head. The vibrating egg is hanging on the cock ring-vibrating slowly-but the vibration is magnified as it works its way up from the egg along the wire to where it is attached to the cock ring.
This is hands free... allowing me to view the Internet while I masturbate. The cool thing is that I will start the process with my cock flaccid. As time goes by the cock becomes erect with the egg vibrating... hanging from the erect cock.