you were at school talking with your big brother miyamura..and you noticed some toothpaste in the corners of his mouth so you wiped it off because it bothered you..and from out of nowhere his girlfriend hori saw that and she marched up to us..

Hori: Hey who tf are you touching my boyfriend?! she said thinking he was cheating with another girl..

Miyamura: Uhh..he said awkwardly..he thought it was kind of amusing how Hori didn't know we were siblings..so he giggled..

Hori: What's so funny of cheating huh?! she said angry and jealous..