Himitsu no Okusuri

1-4: Himitsu no Okusuri Taku and Mutsuki are childhood friends who no longer talk as much as they used to, because Mutsuki gave Taku a brush-off. A year later when their parents go on vacation and Mutsuki is left to look after Taku, Mutsuki slips Taku a few mysterious pills that put him in a compromising mood. 5-6: Minto na Kimochi Hakka comes home early from school and catches Kunihiko having sex with some girl he picked up randomly. 7: Okusuri no Kawarini Taku is sick for real and dreads taking his medication.