I keep extra rolls in a cabinet in the bathroom. You might want to do that if you have space, (but don't tell the children).
{You can use it for your needs and "hide it again".)
If they find that they need to wipe and the spool is empty, well, they might just start getting the picture.
You haven't failed, they might just be counting on you too much. When my boys got old enough to cook for themselves, I kept telling them that if I dropped dead tomorrow they still would have to eat. Worked for mine, and one is even a better cook than his Mom! :lol: :thumbup: