I think their are multiple couples I don't know but I know that they are neighbors who everyone thought was going out but never really soad they were and the parents talk in the extra about marriage of aons
the only one i can think is http://www.mangago.me/read-manga/samishigariya_no_love_letter/bt/342599/Vol1_Ch3/
About a highdchool boy who fell in live with the school nurse and the nurde leaves the school so he can date him but the seme getw goodbgrades i believe
https://www.google.gr/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiT3s34ibbUAhUDaxQKHZKZBBcQFggnMAA&url= http%3A%2F%2Fwww.mangago.me%2Ftag%2Fschool%2Bnurse%2F&usg=AFQjCNHZf25-0bKzIHmyTP68RXtAle3mWA
There is a scene where they go to the beach and wear pink swin trunks but the uke ends up in a bikini bottom that is pink they have sex at the beach
Free Kisses? The last chapter.