Help me find bl manwha

I’ve been searching for the past few hours and I remember very little. first it is modern day (college?) bl im pretty sure. and I remember a scene where the mc’s relative (sister?) is outside trying to get me to introduce ml to her and the mc ends up getting slapped by sister (or ml or ml slaps sister for saying something rude) idk but someone definitely got slapped. please help me thank you ┗( T﹏T )┛