Mutual Feelings ( sunsun au ) Where both Sunoo and Sunghoon got a call from the school that their little brothers fought, instead of solving it, they ended up fighting too. This is sunsun au is written by @loveksnoo from twitter credits to her! Now, I'm reposting this so that everyone can read her au's btw, don't forget to follow her account. Author's twitter account : @loveksnoo