Hi! I'm looking for this manga where this girl (side character) falls in love with her brother's friend (main guy) and then he rejected her after she tries to have sex with him when she couldn't even unbutton his shirt and he laughed at her. She then ran away and her brother (in love with the main girl) found her and said to go home and then he said a pair of siblings who just got rejected and she got all mad at him. This is just a short part of the story I remembered. If anyone knows what this manga is called, please tell me!

That's happens in Rockin' Heaven chapter 15-16, but I'm not sure if it's in another manga as well.