@Name. The couple that I believe you're referring to (the ones towards the middle/end of the chapter first at the restaurant, then in the bedroom) is Hyunsuk (lighter hair, pinkish eyes) and Woo Young (darker hair, grey eyes), these two are the side couple. Hyunsuk is the bottom and Woo Young is the top. With the main couple (the two shown at the beginning of this chapter), Hyuk (darker hair, blue eyes) and Yoojoon (lighter hair, light brown/tan eyes), Hyuk is the bottom and Yoojoon is the bottom. I hope that helped!