Place it at the reveal point of a reaction edit, after a brief build-up clip and before a follow-up laugh. Pair it first with the tuturu sound for a second interjection, then close with the anime ahh sound to keep the sequence in anime territory.
About this sound
This is a two-second voice clip of a girl exclaiming 'oh my gah' in a high, drawn-out tone. It feels playfully shocked and over-the-top cute, turning a small surprise into a big reaction. The line comes from the anime Kiniro Mosaic, where that English exclamation became a memorable character moment.