
I'm not sure if there are any sequels, but if you mean bonus episodes/clips, then
- https://youtu.be/8CT1Sco4P4U
- https://youtu.be/abYK7ZJgfOY
- https://youtu.be/0_Hy5faytRI
- https://youtu.be/bK0wYv46aPc

Hey! So, I looked it up and found this: http://adultdigitaldownloads.com/kor-eng-lewin-%eb%bf%a1%eb%b9%b5%eb%80%a8-hyperventilation-gwahoheub-%ea%b3%bc%ed%98%b8%ed%9d%a1-2017/. The video is a combined version of season 1 and 2.
Is this the right sequel? I'm so glad I stumbled upon your comment. I wouldn't have known about the sequel at all. ε=ε=(ノ≧∇≦)ノ
Does anyone know where I can get the sequel of the animated version?