Yoon Yerin

Jinsoo first meets Yerin (prefers to be called Rin) while working part time at Yoonji's parents guest house during summer break. She seems to stay at the guest house yearly and enjoys meeting up with men for sex. While asking Jinsoo for customer service she seduces him in having sex as well. They later become somewhat friends and even end up having a threesome with Ahn Dajeong then adding Yoonji into a foursome. Rin is very open when it comes to sex and even incourages Jinsoon to have a harem. Later it's reveals she's related to Jinsoo's former sex friend and crush Yeseul.