Place it just before the reveal in your edit, after a short build-up, so the payoff lands straight after it. Follow it with the Vine Boom, or lead into it with the Dun Dun Dun to hold the build-up a beat longer before the moment breaks.
About this sound
This is a short voice clip, just under two seconds long, of a voice shouting the phrase I'm bout to cum in a hyped, over-the-top delivery. It lands as funny and awkward at once, because the excitement sounds completely unleashed and a little too much for the moment. That blunt, peak-energy feeling is what makes it work as a sudden reaction.