Place it immediately after the moment of impact in your edit, once the hit has landed, then follow it with an evil laugh to close the exchange. For a game clip, open with a Minecraft damage hit first so the line answers something the viewer has just seen.
About this sound
This is a short, roughly three-second spoken line in which a calm, tough mafioso-style voice states that he feels no pain, with a slow, unbothered delivery that makes the boast land. It gives a listener a cool, defiant feeling, like shrugging off a hit without flinching, and works as a dry, confident brush-off rather than an angry threat.