Question: why did yato kiss bishamon?
Answer: Yato finding out that his dad kissed Hiyori and got jealous/angry about it, while Hiyori brought up Yato kissing Bishamon showing her own jealously/anger about said action (though to be fair on both sides, Fujisaki kissed Hiyori and she clearly didn't want/like that and Yato kissed Bishamon indirectly while he was ...