The song was written by Gomez, Gucci Mane, Chloe Angelides, Brett McLaughlin, Gino Barletta, and its producers Jonas Jeberg, Joe Khajadourian, and Alex Schwartz.

"Fetish" received widespread acclaim from music critics, who complimented its experimental nature as well as Gomez's vocals and subsequent artistic growth.

Mike Wass of Idolator described the song as Gomez's "most scandalous" and "most adventurous" offering yet, stating her transformation into "pop's most experimental princess is all but complete."

"[12] XXL writer Peter A. Berry felt the "atmospheric, stripped down" instrumental is "perfect for the bedroom," while Mane's verse "adds an extra layer of dopeness.

"[18] Time's Raisa Bruner called it a "slow-burning, seductive pop song [which] allows Gomez to play with the distinctive textures and rhythms of her voice, developing into a sinuous, alluring track that smartly dispenses with overbearing production, instead focusing in on the star attraction.

Inside a suburban home, the singer is seen soaking wet (similar to the opening shots earlier) in a dining table with water sprinkling as if it is raining, with candles in the scenery.

"[24] The video's stylist Stella Greenspan drew references from Nobuyoshi Araki's photography books and Isabelle Adjani's performance in the 1981 film Possession to achieve a horror-film inspired aesthetic, within a story of a "good girl gone bad".