Get about 7 inches of a 2-inch-diameter PVC pipe; a large, soft sponge that can hold a lot of water; and balloons or condoms. Cut the sponge into a relatively thin, flat sheet about 5 inches wide and 7 inches long, and make the cut sponge thicker on one edge (so you can create a tighter opening). With fishing twine, sew the sponge together so the two 7-inch sides touch each other. The sponge should now form a cylinder 7 inches long. Put the sponge in the PVC pipe so the inside walls of the pipe are covered with the sponge. You can then put either a condom or one of the squiggly "worm" balloons sold at toy stores through the sponge. Make sure the condom or sponge is secured to the outside of the PVC pipe, and make sure the other end is firmly attached to the other end of the pipe. Then simply put hot water in the sponge. (If the sponge is too hot, it might hurt – so wait until it's just the right temperature.) Put some kind of lubricant (hand lotion, K-Y jelly, etc.) in the condom or balloon and slide your penis into it. You might need to make the device several times so the sponge is neither too tight or too loose.