My first J.O to a climax was at the hands of a 16 year old boy when I was 13. This was the most important bench mark in my life. I have jacked off, solo or with a partner at least once a day ever since. Now in my 70's I am sill inventing variations on this never ending theme. As there is likely nothing really new under the sun, this one is a modificatioln I made on others that have appeared hear and elsewhere.
We will start with the material list. You need to purchase about a one foot long length of standard ABS plastic pluminng pipe. It comes in differnt diameters and in either black our white. My cock when hard measures a tad over 1.5' in diameer. So I use the 1.5' inside diameter ABS, which makes for a close but not desirably tight fit. I then take a standard bicycle tire tube and cut a section out that is about 2' longer than my erect cock. This fits loosely down inside one end of the tube. Leave about an inch or a bit more sicking out the top and then roll this down outside the tube. If it resists too much, just heat it up with warm water. You now have a length of pipe (I use white) with what looks like a black (the rubber tube turtle neck olled tightly down its outside for an inch or so. This keeps the loser fitting tube inside the pipe firmly in place, At this point you can give it a pre test by running hot water throug it and seeing how your cock fits in. Ideally, it should be just a tad too tight at the turtle neck entry point without any lubricant. But squeee in after lube is aplied. The lube I have found ideal for this is to squirt pressure caned shaving cream into and around the neck. Once you et the bulging carona end of your cock in it will be sliding up and don n the looser, but still toucing inner rubber sleave, also being lubricated by the shaving cream another choice. If your cock does not fit this as naturally as mine, then you may want to line the inside of the tube with a second rubber bicycle tire inner slevee if it is too large, or to hone out the inside of the pipe with either a commercial brake hone (available at any auto supply shop) or a home made one in which you take a length of doweling, make a lengthwise cut in one end into which you insert strips of medium to course sand paper. Attach to a portable drill and just polish it to a larger inside diameter. If you don't ave a portable drill you can make a similar one that you just pump up and down manully using the armstrong method. That takes longer, but its in a good cause. In any event, when you the get the diameter right, it is the closest thing to a real vaginal skin to skin effect I have ever exerienced, and you can customize how tight you want your home made pussy to grip your best friend using the above adjustment means. While this may be enough to send you to erotic heaven, there is more. This is why I recmomended a one foot length of ABS, obviously more than required just to grip it and start wanking. The extra pipe is to provide for a pussy temperature control as well as the sensation of finding the soft tissue around the G spot at the far end of your in stroke. This is achieved by taking a soft plastic foam spunge of the kind intended to clean up around kitchen sinks which measure about 2x3x5 inches and come in a number of colours (pink being perhaps the most appropriate). All that has to be done is to put this spunge in a sink full of hot water that is just a bit warner than feels comfortable when you dip the end of your cock into it. You then load the spunge with this water and comress it sufficently to stuff it down the other end of the pipe. If it it is so tight that most of the water is squeeed out, then cut it back a bit with scisers or a knife. What you are looking for is enough water being retained in the spunge after it is squeezed in to surround the end of your cock when you push into it on the forward stroke. After you get the spunge set so it fits snugly inside the pipe at a point where its front end is at a distance that your cock head will push into it on the forward stroke, then you can about one-half fill the rest of the space in the pipe to the rear of the sponge with the hot water already mixed and tested to be at the temperature that you can cofortably insert you cock. All that now remains is to cap this far end with a standard pipe cap for the size pipe you are using (purchase at same time you buy the pipe). For plumbing purposes, this cap is meant to be glued in place. But for our purposes, it fits well enough to keep the water in and is best left removable for later cleaning and adjustment convenience.
If all has been set up right, we now have a device which feels the same as a nice tight pussy when you insert your cock, The deeper you thrust the warmer and wetter the sensation on the back stroke there is a distinct suction sensation as the 'piston' (your cock) draws the warm water forward creating a partial vacuum. On the forward stroke there is a sense of resistance as you force the water back into the pipe through the low resistant sponge. When the tip of your cock bums into the sponge, it senses the now slightly pressurized warm water oozing out over it. All the time, your cock is being squeezed slightly by the inner tube, which also lets you slide through it thanks the lube on the inside. The sensations are both dynamic and thermnodynamic. You can hand wank the pip over your static cock or tie the pipe down and thrust with your hips.
When finished, if you have the strength to do anything but bask in the afterglow a great orgasm, you simlpey take the cap of the far end, then insert something like a dowll or cut off broom handle through the insertion end of the pipe and push the comressed sponge out, leaving the inner tubing in place. Then rinse everything and leave it to dry for next time. An addeded advantage is that if you leave it with your home fixit tools , no one would have any idea what its real purpose was. (If you have another guy as partner, you can double end this arrangement, leaving the sponge at the center point and simply add the turtle neck tubing to both ends. The hot water can be added at both ends.) Have fun and let us know if you make any improvements.