Lee Yeon-Doo in nude scene from Gangnam Blues which was released in 2015. She shows us her tits in sex scene.
Also Kim Yoo-Yeon naked in Gangnam Blues. We can see sex scene with her. So Kim Yoo-Yeon is not shy and she demonstrating her boobs.
In addition there is scene with nude Seol Hyun. Thanks to Seol Hyun for her tits and other sexy shots in that video.