I've seen a few questions about this condition so I'm posting a report I did a while back.
Postmortem male penis movement, a/k/a Penis snaking
Is it true, or just a nurse’s tale?
Like any tale or legend, there is always a certain amount of truth within them. I have witnessed this phenomenon personally in a morgue and asked a pathologist to explain how it occurs. So here goes.
If a man dies on his stomach or side, the blood which remains in the torso attempts to move to a lower position due to the gravity. As the blood in the waist (which cannot move down due to the legs being full) causes the penis, consisting of erectile tissue, to fill with blood and expand. This is the death erection, a/k/a angel lust. As long as the body remains in this position, the effect will continue.
Now, say if the man died on his side and was left that way when he was transported to the morgue, the erection would hold. The anatomy of a penis consists of the visible penis and almost an equal amount of that, is internal.
When rigormortis starts setting in sometime after 4-6 hours as his pelvic muscles begin to tighten, it causes a reaction to the internal part of his penis that, in turn can cause his external erect penis to move in uncontrollable motions. This is where the nurses’ tales kick in. I have had nurses say that they have grabbed the penis and couldn’t stop it from moving. Others say they tied a string to a man’s snaking penis, then tie it to a chair and watched his penis move the chair, etc. These are all exaggerations. It’s akin to a corpse to sit up, which is almost impossible. There can be some movement of a corpse when going through rigormortis, but never that much.
If a female wanted to have sex with a dead male that had an erection. What would happen, if she put his body on its back? Well, the blood in his penis would drain back into his body and his penis would then become flaccid. If she were to put on a tight cock ring at the base of his penis, she could maintain his erection for as long as she wanted. “Ride him Cowgirl!”
Say a female has a good looking male corpse she would like to do, but he’s flaccid. What could she do to make him erect? The anatomy of a penis has two arteries and one vein, running the length of it. (See illustration next page). The vein is visible on most men, running for the most part down the top center of his penis. On either side, deeper down are the two arteries supplying each side of the sponge like tissue, which blood enters to cause an erection. The vein is for the blood to return to the body. During an erection, the vein constricts, which keeps the blood in the penis.
To make the males penis erect, will require some knowledge and talent with a hypodermic needle and syringe. To start, put a cock ring at the base of his penis to keep the saline solution you are going to use from going back into his body. Then on each side of the vein, locate the arteries and start injecting them with the saline solution while massaging his penis briskly, which will help the flow of the solution. You don’t want his penis to get too lumpy now do you? If you’re successful, you will have an erection that you can use for as long as you wish! Just don’t get caught!
A second way to make a postmortem erection is by inserting a metal shaft down his urethra. I suggest a piece of round aluminum stock: 5/16”- 3/8” dia. Approx 8-10” long. Lubricate it well and work it down his urethra until it is at least ˝” below the head of the penis. Then, either stitch the head closed to keep it in place. (This done correctly, can make a nice French tickler.) Or, you can use CA glue to close the urethra. Just make sure you have a deactivator for the CA glue, so you have the option to undo the CA glue to remove the aluminum shaft when you’re finished.
So have fun and play safe!