Vibrator and Clamp

I use a Whal Pro Series 2 speed massager with a contoured attachment that fits around the head of my penis, and a clamping device to hold the massager. I then place the massager and clamping device between the mattresses and adjust the height to fit to fit my penis when in a kneeling position. I start out on low speed for a few minutes and then change to the hight speed. I can ejaculate as quickly as two minutes or prolong it as long as I wish.