Boku no Sexual Harrasment

Can anyone explain what happened in Boku no Sexual Harrasement


What's with the ending?

Was Junya (the uke) being used by Honma (the seme) or was it something else??


What was the significance of the boat, firefly scene that we see in Junya's Flashback???



excuse me if I'm stupid or ignorant or whatever╥﹏╥