Guys lets not forget Koh called Jira constantly when he was about to have sex with Pheem because remember Koh said himself to have Jira's location. He knew where he was and remember Pheem said he and Koh have been competitive since they were kids! Koh is making moves to Jira because because he wants to win and not Pheem.
Jira is trying to direct his attraction for Koh towards Pheem, ..he’s giving him false hope or perhaps pheem…
Pheem is so toxic he literally said he wants to ruin Jira so he can rely on him. Jira clearly does not like Pheem, he looked uncomfortable but is seeking to sleep with him anyway.