Place it at the instant of impact in a fail edit, then follow with Roblox Oof for a second character's reaction before Doge Bonk closes the gag with a heavier hit.
About this sound
This is the short grunt a male Terraria player makes when he takes a hit, a clipped retro-style vocal burst that finishes in under a second. It lands as a light comic sting, amused rather than dramatic, suited to a small slip instead of a big defeat. The sound comes from Terraria, the 2011 sandbox game from Re-Logic, where it plays whenever a male character is hurt.