Responses
https://www.mangago.me/read-manga/nazelove_when_a_student_council_member_educating_their_junior_somehow_turns_into_a_romantic_comedy/ ?
Might not be it but has somewhat the same scenario
Tachibana x takahashi chapters^
And the couple is so horny for each other but exams are coming up and prez has to focus so he locks uke out? Or something? I don't remember much about it. They're not the only couple in the story too, more like a side