Buy a electric massager from your favorite store.
Lay in bed, naked, and place the massager head on the underside of your cock and balls.
You can use pillows to secure the massager so it will stay in place.
You can play with your nipples while the massager is doing its' job to get you off, hands free.
This technique gives awesome orgasms.
Most massagers have 2 speeds. low and high.
I start out with low and then when I'm about to shoot my load switch it to high and watch my cum spurt out. Your whole body will shake with delight.