Teach back is an interesting idea which seems to have wide application. The idea is that when you've explained something, you ask the patient / student / teenager to teach it back to you. Of course most of the time they can't, confirming they didn't have a clue what you were going on about (or maybe that's just me).
Like I say, an interesting idea, but does it work? Probably, at least in the short term.
I've also heard a variant suggested as a tip for helping in early dementia - if someone keeps asking the same question you get them to repeat the answer back to you. The theory is to do that in converting hearing info to speaking it, various brain processes are required which help to retain the information longer. Works for remembering people's names too: 'Hello I'm Peregrine' 'Hello Peregrine - nice to meet you.'