Put it at the end of a fail sequence, after the Vine Boom has marked the impact and the SpongeBob Fail has underlined the embarrassment, so it closes the gag instead of starting it.
About this sound
This is a short clip of a person laughing, lasting under two seconds, with one clear laugh that is easy to recognise at once. It gives a scene an instant funny, slightly mocking lift, turning a stumble or an awkward pause into something to laugh at instead of wincing at.