However, based on the show, here are some possibilities:
* Katara: While not known for being particularly romantic, she shares a kiss with Aang in the finale and likely had some romantic encounters with Sokka, especially in the later seasons.
* Sokka: While not shown on screen, he's hinted at having a romantic relationship with Suki and might have shared some kisses with her off-screen.
* Zuko: He shares a passionate kiss with Mai in the finale of Book 3.
Ultimately, there's no definitive answer to who kissed the most, as the show didn't dwell on romantic relationships in great detail. However, these characters had the most onscreen kisses and are likely the ones who had the most romantic encounters.