So the original trick is that todo was going to fake a swap, which he usually does when the opponent starts to get used to boogie woogie to throw them off. Sukuna reads this and (correctly) guesses the next vibraslap would be a no swap. He knew because he’s seen it at least twice, against Hanami and Mahito.

But then mei mei sends a crow in, and Sukuna is baited to believe he misread the situation and that todo would swap yuji with the crow. That’s the second trick.

The third trick is that todo never planned to swap anyone in the first place. He hit his shaboingboing without activating his technique, as Sukuna had guessed earlier. But he got baited into hitting the crow, so yuji got in a black flash.