Well, I never seen the word, except for ctr.
Your choice of words tickles me again.
There is no "mandatory clickthrough". The age check is an emergent detail and not the thing this about. You will not get the age verification if you prevously checked it with yes. Or if you have the setting checked to show content marked as adult. The setting will even be ignored, when you select one of the adult tags (like 'adult').
If you want to look at an analogous situation, skim the psa thread about discord scams. You can't report such a page, if you were not the scammed user, since you can't even access the page to click the report button. There will not be any additional contact support buttons, just so people do not have to write the subject of the mail. They still have to write the complaint with details anyways.
To end this with trivia, If there are circles that use the word for the actual confirmation message and not the whole process, I wanna bet, it started as something like clickthrough dialog or even clickthrough pop up.