I had never previously said totes amazeballs and don’t ever expect to again, and in fact the sooner it dies the better, but a lesson on ‘extreme adjectives’ was good much of an opportunity. The textbook had several synonyms for ‘very good’ and I elicited several more, then mentioned that people make up their own, including totes amazeballs. (Another is fantabulous.) One student expressed great doubt that such an expression exists, but I was able to show her on Google. (Most sources on the internet cast scorn on the expression and the people who use it.) She couldn’t figure out how a word ending with ‘balls’ can be an adjective. Basically, it can be an adjective because people use it as an adjective.
Another point is that terrific, terrifying and terrible, and horrific, horrifying and horrible should mean the same thing, but don’t. I didn’t mention Latin – I just said “Be careful about these words – they are different”. (Horrific didn’t occur in the lesson – I just mention it for the sake of completeness here.
I’m not quite sure exactly how I know this expression. No-one I know uses it. I’ve just read it on the internet enough times for it to sink in. The downside of being passionately interested in language.