Place it right after the winning shot in your edit, then follow it with Bruh for a deadpan reaction before the next clip starts. For a bigger roast, put Emotional Damage after it instead, letting the taunt land first and the reaction carry the joke.
About this sound
This is the Sniper from Team Fortress 2 letting out a slow, smug chuckle that stretches into a long, drawn-out heeeeeeeeeeee over about three and a half seconds. It feels cheeky and triumphant, like a marksman who knows his shot just landed exactly where he wanted it. The clip comes from the game's Australian sharpshooter, whose dry laugh has become a familiar taunt in matches.