Mich's manga / #Poly couple(1)

I thought it was gonna be yaoi at first tbh. Wasn’t too bad but the fact that they just blindly accepted the new girl and that they somehow always did it in the station at first without getting caught??? Well by more than one person… also long haired obv likes black hair more so they should’ve all talked about their dynamic in the relationship. Like are they a couple with an extra FWB or is she actually also part of the relationship and not just a friend. Won’t long haired get jealous if black hair starts to confide in short hair more