Place it at the peak of a confrontation, just before the reaction shot, then follow it with the Vine Boom Sound Effect to underline the fallout. For a longer scuffle, put the Classic Punch Sound Effect after it so the exchange escalates from a single hit to a full fight.
About this sound
This is a very short, sharp slap lasting under a second, with a crisp impact that suggests a quick smack across the face. It feels sudden, cheeky and playfully dramatic, turning a small reaction into a bigger joke. It is a generic impact effect rather than a line from a particular scene, which is why it works in so many different edits.