This is the first Shinjo Mayu anthology in the set of 3 titled Mayu-tan no Tokimeki Note #1.

1-3) TABOO ni Daite Asou (Embrace Me in TABOO)
Yayoi is a high school freshman. Her parents died when she was very little, and so now she lives with her older brothers Naoki, whom she goes to school with, and Tomoya, a medical student....