There was this curious kids toy... that I'm not even sure is still available... that I used to use to masterbate my penis. They were called 'soccer boppers,' and they came in a pair, even though all you needed was one.
Soccer boppers were like kids boxing gloves, only more like small beach balls. You would blow them up and slide your hands in each one and proceed to beat the heck out of each other... Well, for fun of course. Being the less violent type, I found a much better use for them.
I would get naked, grab my sister's big mirror, and my favorite porn magazine, and some lotion. As my penis got harder anticipating the fun ahead, I would squirt some lotion in the opening of a full-blown soccer bopper (where your fist goes in), place the soccer bopper on the floor, and watch in the mirror as I inserted my now erect penis. The hole was very tight around my penis, especially from the pressure of lying on it, and lifting myself up and down so my penis would slide in and out.
Mmmmm, it felt so good, and to watch myself in the mirror was way cool.
The best was yet to come though. After watching my hard penis slide in and out and my ass arch up and down for a while, and build up a huge cum looking at my magazine, I would squirt a huge load in the soccer bopper. Again, mmmmm...
Then I would hide the soccer bopper upright for next time. Why? Because the next time I slipped my hard lubed penis in the hole, my head would touch the now chilly cum left in there from before. And the smell that came out when my penis went in was awesome! I can't explain how arousing the combination of the cold cum on my penis head and the smell of the cum was. And I would cum in the hole maybe ten times before I would clean it out, so it got pretty deep in there at times.
Please try this technique... you won't be disappointed!