I haven't seen it but I'm guessing they are talking about when you do a layup and you tap the backboard... if you don't get it maybe someone in real life can show you.
Edit: I just did a quick run through and saw this backboard tap. It looks like this (it's the last layup).
You can tap the backboard after a dunk and also use the backboard on a freestyle block.
Its automatic depending on the position you block from or where you jump for your dunk, i'm trying to figure out the lay up one, will update, but for sure, the block is automatic depending on where you block from.