In December 2020, Lavigne confirmed she was recording music with Mod Sun along with producers John Feldmann, Travis Barker and Machine Gun Kelly.

[13] Mod Sun and Avril Lavigne confirmed that they were making a new music video for "Flames" through their social media posts and comments in response to fans.

Tamara Bay of Wall of Sound wrote that the song is "an emo pop jam which sees Avril and Mod Sun's vocals ebb and flow together like two peas in a pod".

[1] Music Feeds' Laura English praised the song calling it "a catchy bop that mashes pop sensibilities with emo AF lyrics and vocals".

Rachel Dowd of Alternative Press praised the song by saying that it "opens up with Lavigne and a haunting piano before heavy rock guitars and percussion kick in along with Mod Sun's distinct vocals.