Ep. 5: Nayu seeks support from Keigo and Komachi to form an underwear society after club dissolution.
Aired on February 1, 2010

5
Following the collapse of her underwear club due to a peeping tom incident, Nayu feels depressed and turns to her step-brother Keigo Hayama, who has lived with her since their parents died, for comfort. Komachi, feeling responsible for the incident, visits Nayu to suggest creating an appreciation society rather than a club. With the decision to establish an Underwear Society finalized, Nayu invites Yako, Haruka, and their advisor Tamaki to an overnight meeting. Despite these plans, Nayu remains preoccupied with thoughts of Kiyono Amahara's words, which she cannot shake from her mind during this transitional period.
Episodes
- Ep. 1 · Nayu Hayama exposes adult panties at Ounan Middle School entrance ceremony
- Ep. 2 · Nayu helps Yako after her bra fails during PE class
- Ep. 3 · Nayu seeks to join the Crafts Club but faces rejection over underwear display plans.
- Ep. 4 · Nayu recruits models for underwear guidance while Haruka overcomes insecurity.
- Ep. 5 · Nayu seeks support from Keigo and Komachi to form an underwear society after club dissolution.
- Ep. 6 · Nayu proposes bra assembly to maintain harmony within the Underwear Society group.
- Ep. 8 · The Underwear Society visits a seaside ryokan, leaving Komachi embarrassed after he wakes up in underwear.
- Ep. 9 · Yako’s awkward incident with Kota and Haruka’s confusion over her chest pain at the summer festival.