Responses

1. The cover of the manga depicts who is on the receiving side of the relationship
2. The height difference in the manga is another BL cliché - also gives a clue to who is top and bottom
3. In Chapter 1, when Oto confessed to the protagonist, most readers would think that he'd be the bottom... but the growth spurt in Chapter 3 says otherwise...
Conclusion: We now know their roles.
(P.S i honestly don't like using the terms top and bottom to describe characters cos I find it to be somewhat demeaning, but i had to say it here cos u might not understand even after the explanation)
i looked at the cover of the manga, then at the height difference between the two in chapter 3, THEN I REMEMBERED how short oto was in chapter 1
THEN EVERYTHING CLICKED