Vibrator
Simply strap a vibrator to your cock, one that suits you, with either scotch tape or an elastic band. I suggest you stay away from the duct tape, the pain is unbelievable. You may have to fumble around with the elastic before you get it right. I have had many great orgasms riding a wave of pleasure that can be almost unbearable, plus your penis feels great afterwards from the massage you have just received. This is also a great way to masturbate hands free. You can read a book or magazine or even work at your computer.