"Wag-Zak" was written by Seo Ji-eum and composed by Razer (Strike), Hongdi, and Jaeripoteo.

[2] It was described by Billboard as vibrant tropical house beat song with a breezy melody that bounces along rhythmically towards its refreshing chorus and the sudden pronouncement of the titular phrase.

[3] On June 21, Woollim Entertainment announced that Lovelyz would release their special digital single titled "Wag-Zak".

[4] Lovelyz performed "Wag-Zak" for the first time at Mnet's M Countdown on June 28,[5] following in the various music program for a week.

The video shows the members of Lovelyz hanging out together on a resort, enjoying games, cocktails, water gun fights, and more.