To explain what is going on here, you basically need to deconstruct the ritual spot immediately after the ritual effect happens. If you're fast enough, the effect will go through, but you'll get a pop-up about the ritual being cancelled. Then you can immediately perform the ritual again without a cooldown. The second ritual spot is there for demonstration, it is not required for the exploit.

You can see the victim's age change if you watch the age in the HUD element in the bottom-left. That is what I was looking for as a cue to deconstruct the ritual spot. Then you can see the ritual is available right away in the second spot when I click on it.