[6] The song was released alongside its music video and the extended play on March 27.
[7] "Good Girl" was written and composed by Brave Brothers, with Red Cookie participating in the composition and arrangement.
Described as a baltimore club dance song with lyrics telling "the lively story of the MZ generation".
[8] "Good Girl" was composed in the key of E minor, with a tempo of 150 beats per minute.
[10] Prior to the release of Hashtag#, on March 27, 2024, Candy Shop held a live showcase aimed at introducing the extended play and its songs, including "Good Girl".