The Big Mouth season 4 soundtrack includes cast performance numbers, along with familiar mainstream songs that typically close each episode. Given the amount of jokes and all the madcap dialogue in the Netflix series, the musical moments are relatively sparse throughout the 10 episodes. However, the character performance numbers are surprisingly poignant, and they thematically contrast with the majority of the humor.
Big Mouth season 4 begins with Nick Birch (Nick Kroll) and Andrew Glouberman (John Mulaney) clashing at summer camp. Meanwhile, their mutual friend Missy Foreman-Greenwald (Jenny Slate) changes her look but can't quite figure out who she wants to be. Nick and Andrew renew their friendship after the latter experiences a nasty bout of constipation, which is spotlighted with a grandiose performance featuring a singing rabbit. The second half of Big Mouth season 4 focuses on Andrew's growing insecurities and Nick's romantic feelings for Jessi Glaser (Jessi Klein).
The Big Mouth season 4 soundtrack includes songs that only play for brief snippets, while the performance numbers are extended and full of animated flair. As always, "Changes" by Charles Bradley serves as the theme song for each episode, and the series even pays homage to the original recorded version by an iconic metal band.
Big Mouth Season 4, Episode 1: "The New Me"
"Previously on Big Mouth" by Ensemble: Big Mouth season 4 begins with a season 3 recap song from all of the main characters. The lyrics cover all the essentials for streamers and establish the camp premise for the opening episodes.
"Mosquito" by Yeah Yeah Yeahs: After Nick realizes that Andrew and Seth have been bonding, he experiences a panic attack and meets Tito the Anxiety Mosquito. As Nick thinks about being a dead and lonely little virgin, "Mosquito" kicks in as the episode ends.
Big Mouth Season 4, Episode 2: "The Hugest Period Ever"
"Crimson Wave" by Tacocat: Mark the Tampon helps Jessi navigate her period wave and consistently provides emotional during the process. Meanwhile, Connie the Hormone Monstress (Maya Rudolph) similarly helps Jessi get through the experience. As the episode ends with a celebratory freeze frame, "Crimson Wave" serves as a musical exclamation point.
Big Mouth Season 4, Episode 3: "Poop Madness"
"Poop Madness" by Brown Rabbit (Mark Rivers): When an angry piece of poo threatens to overtake Andrew's body, he's briefly entertained by a well-dressed rabbit who sings a psychedelic tune about extreme bowel movements. The lyrics reference the lasting effects of a rectal strain reaching the brain, and the rabbit even manages to rhyme "dance of fools" with "stubborn stools." By the end of the "carnival of constipation," it all becomes too much for poor Andrew, as he es out face-first in the forest.
"I'll Stand by You" by The Pretenders: After Andrew experiences "poop madness," Nick literally finds him with his pants down next to a tree and reveals that he has missed his old pal. The heartfelt reunion allows Andrew to the angry poo through his system, which poignantly sets up a cover of "I'll Stand by You." The scene plays out like a birth sequence, with the two friends bonding through the intense ordeal. The Pretenders' original version of the song closes out the episode, as Maury the Hormone Monster (Kroll) reveals that he named Andrew's twin poos Zack and Cody, stating that "I think they're gonna have a pretty sweet life."
Big Mouth Season 4, Episode 4: "Cafeteria Girls"
"Cafeteria Girls": Nick and Andrew realize that all of the eighth grade girls have boyfriends, so they attempt to impress a couple of seventh grade girls named Izzy (Anna Konkle) and Misha (Maya Erskine). As it turns out, they're the stars of a TV show within Big Mouth called "Cafeteria Girls," which includes a theme song with the tagline "Life is their tray-hey-hey." Nick and Andrew are surprised to discover that Izza and Misha believe the boys are part of their show, and not vice versa.
Big Mouth Season 4, Episode 5: "A Very Special 9/11 Episode"
"Code-Switching" by DeVon (Jak Knight): In New York City, Missy learns that DeVon has a special code switch on his arm, which allows him to activate different voices depending on the situation. DeVon then performs a song about Black kids who feel the need to put the world at ease.
"Bury A Friend" by Billie Eilish : The episode ends with Nick looking out a window and thinking about his romantic feelings for Jessi. Thematically, Eilish's 2019 single sets up the following episode that takes place in 2052.
Big Mouth Season 4, Episode 6: "Nick Starr"
"Changes" by Black Sabbath: The original version of Big Mouth's theme song plays during a 2052 dream sequence about Nick growing into a soulless TV personality named Nick Starr. The song plays again during the final seconds as Rick the Hormone Monster (Kroll) reunites with Nick.
Big Mouth Season 4, Episode 7: "Four Stories About Hand Stuff"
"Hands to Myself" by Selena Gomez: The song briefly plays during the final seconds of the episode as Maury the Hormone Monster and Connie the Hormone Monstress have a meta conversation about the preceding events.
Big Mouth Season 4, Episode 8: "The Funeral"
"Used to Be Her Favorite" by Matthew MacDell (Andrew Rannells): Matthew performs a solo ballad after his mother takes him off the bake-off team for being gay. There's no comedy within the dramatic number, as the character reflects about his childhood and his belief that the "unspoken" had been understood by his mother. The tracks ends with Maury the Hormone monster holding Matthew, and stating "F**k her, you sing like a goddamn angel."
"Jesse" by Carly Simon: The song briefly plays at the end of the episode as Jessi says goodbye to her mother.
Big Mouth Season 4, Episode 9: "Horrority House"
"Lola & Jay": The French-themed song plays during a Halloween sequence as Lola Ugfuglio Skumpy (Nick Kroll) and Jay Bilzerian (Jason Mantzoukas) imagine themselves as outlaw lovers with "a boner for crime."
"Gotta Get Up" by Harry Nilsson: The 1971 song plays during a dream sequence while Andrew is stuck in a coffin and decides to "yoidle" his "doidle."
Big Mouth Season 4, Episode 10: "What Are You Gonna Do?"
"Whatcha Gonna Do?" by Rick the Hormone Monster (Kroll): The season ends with a performance by Rick the Hormone Monster, who sings a folk-y song about staying strong in the face of adversity.