Choi-S's Seito and M's Riko had matching sexual preferences and were a close couple. One day, to introduce Riko's best friend Sora to a man, they planned a hotpot party with four people by inviting Seito's friend. However, just before the event, Seito's friend couldn't participate, so they reluctantly decided to have the hotpot with three people instead. Sora, who was asked to buy alcohol, accidentally witnessed Seito and Riko having sex. Seito felt awkward after being seen in the act, while Riko knew nothing. At the hotpot party, Riko quickly got drunk and fell asleep. The mischievous Sora then began to torment Seito's nipples...
