“Wag-zak” is an onomatopoeia for the sound when one chews on ice.1
Member JIN did not participate in this song due to health reasons.2
https://twitter.com/geulyz/status/1011603123159396354 ↩︎
https://www.sbs.com.au/popasia/blog/2018/06/22/lovelyzs-jin-latest-girl-group-idol-take-break-due-health-issues ↩︎