Back when I was young, between girl friends and wanting to get laid, I found this great substitute. As some point I noticed that the cardboard center of the toilet paper roll fit perfectly around my penis. Not much I could do with that, too abrasive, until an idea came to me.
I put some lube in a condom and put it on, then I put lube all over the outside. I inserted my penis into the tube and moved it in and out until it was all lubed up. Now where to put it? Oddly, I tried between the mattress and box spring on my bed. Too tight! My sneakers were on the floor, so I put one on each side of my penis. Too loose! So I moved them each out a bit, and... Oh my, this was just right! So I started humping away at my bed, thrusting in and out of the toilet paper tube. It felt incredible, and I rode it to a very intense orgasms!
Going forward, I didn't want to get lube all over the mattress, so I put the tube into an old sock. Complicated set up, but once I figured it out, it was a regular activity of mine.
Give it a try and let me know what you think! ;^)