Nasty Nasty has released a back stage clip during their unit debut stage for 'Knock' at M!Countdown.

Even though having sexy concept, the three members, Kevin, Kyungri, and Sojin are bonding well and very comfortable with each other.

ZE:A's Dongjun was also present to support them and even became floor manager during the stage performance leading the fans' support cheer. Check out the clip below: