Longsword sheathed attack

[Post, Son of Yawgmoth]

Hi I just bought iceborne 2 days ago and have been playing. I noticed a new move I've never used before on the longsword, idk if I 'd just never noticed it before or if its new with the DLC, but its a move where I jump back a bit and sheath my sword like a samurai, and I can hold it indefinitely, upon release I slash foward. this happens at the end of the spirit combo instead of the roundhouse slash. Can anyone explain this for me please?
thanks in advance!

[Suzaku]

https://www.youtube.com/watch?v=u6zs2JMsIS4

[Post, Son of Yawgmoth]

Originally posted by Suzaku:

https://www.youtube.com/watch?v=u6zs2JMsIS4

so it is a new move, thanks

[Bong-B Rippins]

You can practice the special sheath attacks on the exploding barrel in the training area, by the by. Good way to get an idea of exactly how tight the timing is.