Basically this glitch works by inputting A+B, releasing it, then inputting and holding it again. Inputting the 2nd A+B from frames 2 through 17 results in getting a full-charge A+B's damage with the speed of regular A+B. When the 2nd A+B is pressed on frame 18 or 19, it does two hits for 88 damage. I've also managed to get 92 once but I'm not sure how.
I'm not sure who to credit for discovering this (it wasn't me) but I felt like this should become common knowledge now that Evo is over (and because it needs to be fixed if there's another patch).