I'd just like to say, Mazerin is dumb, and all 3 slashes are blockable, ezpz. If you can blocktap well, it's not hard.
I'm in iTeachTBF (Yeah, I know, alot of people hate it.
) and I can TBF pretty well...
Here's tips on doing it :
Practice DBFing under lower ceilings.
Practice floating off of an edge (slashing off an edge 'till you fall off and float) and then slash/blocking over and over, getting it as fast as you can.
Practice BF hang. This is where you jump slash block then wall-hang. This takes alot of practice, but it's how fast your first slash needs to be.
Lastly practice "landing", this is slash-blocking right before you touch the ground. The easiest way to get the timing is to practice doing two FULL slashes in one jump with no blocks.