Short affectionate voice clips like this circulate widely in anime and meme communities, where a single cute phrase becomes a reusable reaction. Similar sounds such as onii-chan onii-chan and tuturu spread the same way through edits, streams and comment replies. The exact source of mommy kisses is not documented, so its popularity comes from usage rather than a known scene. Creators keep reusing it because the soft delivery works both sincerely for wholesome moments and ironically for exaggerated romance, teasing friends or punctuating a character acting especially clingy and sweet online daily.