I am predicting that next week's comic will have something to do with how Rui's hair is too short for regular twintails. :-)
Cat ear peace!Gyaru power on full display!Sousai Shoujo Teien Activity DiaryTwintails 2nd-year class Part 2 SeiraGyaru peaceChin hold poseWhat I can find is that this is a slang interrogative phrase associated with Gyaru types.Twintails +Click
(camera sound)