Basically after doing the 2,1,2 string into teeth on hit. If you do a meaty b1,3 the over head 3 hits at the same time as the exploding teeth. It is a hard to blockable that launches. You can adjust the timing on the b1,3 so the 3 hits after the teeth to mess with people more. It can be wake up attacked out of though.
General Idea
2,1,2 teeth. Early b1,3
The 3 either hits before the teeth or at the same time. To block this they need to crouch block the low, stand block the overhead and the crouch block the teeth. This is very difficult.
If somehow they are able to block this, you can change the timing to do b1,3 slightly later.
By doing it later, they will either stand block too late and get caught by the teeth, or block the teeth and get caught by the overhead (or just block the whole thing). This variation is easier to block, but can be used. The reward is not as great though cuz the b1,3 splats them. You do get a free teeth set up after the b1,3 though.
Generally stick to the early b1,3. Even though you become one dimensional so its easier to block, you have a larger reward.
2,1,2 teeth on block into b1,3 also works if they respect your insta jump 2 beat your jump out attempt. It launches the same and the timing works out almost perfectly every time. But it is more gimmicky as they can hit you out of it. The 2,1,2 string forces a guessing game on block or hit either way.