Ehhh, I think it better to say that it can work. It really depends on the degree of constipation, the reason for it, where it is in the large intestine, and the state of the feces.

But it will absolutely not be like squeezing out toothpaste if the person is constipated enough to need to try it in the first place. If the poop is firm enough to have difficulty exiting the anus, it won't be a gentle push and then out comes the poop all easy like. It will absolutely help, though I would say that digital dilation of the anus would be a better option, and even that only after something like a suppository has failed to give relief.

I'm kinda 50/50 on trying an enema before trying the more direct methods like this, or digital dilation. They can work, but I've seen them fail to clear a blockage and end up just messy. Most of the time, a glycerin suppository is going to do a gentler, better job of helping the rectum clear than manual assistance of any kind.

But gods, anything is better than having to clear the impaction manually. Nobody enjoys that. When you have to essentially dig the feces out, everyone involved is going to be in some degree of pain. And even that's better than the rare instance that requires more complicated intervention. Which, in my twenty years wiping butts and helping clear them out, I only ever had one patient need anything more than manual intervention. And that guy was on enough opiates to knock a horse out, so it isn't a common thing.

No bullshit though, the first time I had to clear an impaction, I didn't throw up, I didn't have to take any breaks, but holy hell did I cry after. I'm a big dude. My fingers are kinda huge as well. So there was no way for it to be a gentle, easy experience. There was a great deal of discomfort for the patient. Poor guy was not exactly happy he was cleared out, though he did later say that it was better.