Is it true that you can cure most cases of constipation in another person by manually inducing peristalsis?

It seems a bit gross, but I have read that you can usually cure someone else’s constipation by inserting a lubricated finger into the sphincter, and rubbing the sphincter and the bottom of the rectal vault quickly in a circular motion. But apparently it’s difficult to do this to yourself, since you already "know" the path of your finger. Sort of like how it is difficult to tickle yourself.

After a while, this should - in most cases - begin to induce peristalsis. The person whose anus is being rubbed will have a strong urge to defecate.

Now obviously this will not always be a first choice for constipation relief … but why isn’t it more popular or well-known in general?

For instance, I did this once for my girlfriend. It provided very fast relief for her, as opposed to waiting for a laxative to take effect, and without the mess an enema can produce.

If two people already have an intimate relationship, this is hardly shocking stuff.

Why don’t more people know about the digital induction of rectal peristalsis?