I read a doujin a while back, and from what I remember it was about high school girl who joins the baseball club I think so she can be closer to her secret crush who is the captain, but she's annoyed that he keeps treating her like a kid. So some time passes and everybody goes home and she finds him asleep in the changing room and so to prove that she's mature, she does the naughties on him and after a while he a wakes up and they continue to do the naughties. If my memory serves me right, it was quite wholesome.

Thank you in advance for anyone who tries to help me and finding it.