User blog comment:Xilinoc/Ch. 577 - SWORD/@comment-14244059-20140417182136/@comment-11051098-20140417233514

"Drink" and "this is makin' me hard" is MangaStream's translations. On MangaPanda the same lines are "Swallow" and "that's great".

Drink / Swallow is said after he jumps up in the air, still holding his sword, before destroying the meteorite after which he wields the giant ax-like weapon. I believe that's all we need to conclude that Drink or Swallow is the release command.