This mid-tempo track was written by American songwriter Priscilla Renea, who also co-penned the girls' "Worth It" and Canadian singer-songwriter Simon Wilcox, whose other credits include Nick Jonas' "Jealous."
The song finds the girls asking their beloved to give them tattoos.
Write on me Color outside the lines Love the way you tat me up Baby come take your time.
Camila Cabello explained on the group's Instagram page. "To me the song is an extended metaphor where you're asking somebody to 'write' on you, envelop you with their words, make their mark on you like you're a blank canvas."
The track has the tropical house-inspired vibe which was du jour in the mid 2010s. In fact, the song was co-produced by Kygo, the Norwegian DJ who helped popularise tropical house. He's joined by fellow Norwegians Stargate who have also worked with the likes of Beyoncé, Rihanna and Katy Perry.