During her sister's pre-wedding trip, she secretly continued to suck her sister's breasts. (Momoiro Family 13, Hachino Tsubasa, SDMF-011)

This "thing" started when his older sister had her first period. The younger brother, a shut-in, sucked on his sister's breasts like a baby for 10 years. Various ways of playing this game give you a glimpse into the "abnormal daily life" of a certain family.