If you masturbate in a position that causes you discomfort you should masturbate in a different position. Sitting or laying down will generally make things easier for you.

If you're going to use something other than your hands make sure it's a material that won't aggravate your skin either because of it's texture or any unsanitary condition. You may need more lubrication than you would with your hands. Be careful, you only get the one penis.

thanks for avice