Big Mouth is an animated show that visually depicts pre-teens going through puberty, which means that it pulls no punches in exploring the ickier side of growing up.
- Andrew masturbates constantly. Anywhere, anytime. When he doesn't masturbate, he ends up ejaculating uncontrollably.
- Anytime Coach Steve gets his shirt off, showing off his man-boobs and oversized areolas.
- Don't touch anything in Jay's house. Odds are he's had sex with it.
- The first episode features a split-second, extreme close-up of Andrew's fully-developed, bushy penis. "Steve the Virgin" and "Smooch or Share" does the same with Nick (albeit underdeveloped and with a single pube).
- Jay tells the other guys about how he turned his pillow into a synthetic vagina by putting warm bags of soup inside it. He eats the soup when he's done having sex with his pillow.
- Jay's brothers are even more disgusting. They ejaculate onto crackers and force the slowest ejaculator to eat the cracker at the end.
- When Rick is announced as Nick's Hormone Monster, there is feces running down his leg.
- Andrew's all-night porn binge ends with him defiling every sock he owns. One even shatters when dropped.
- Coach Steve's lactose intolerance is triggered when somebody says "cheese", causing him to throw up. Things get taken up to 11 as Steve manages to get ahold of several dairy products that make him throw up even more, culminating in Steve licking a cow's teat while the cow throws up.
- Maurice shaving himself "in solidarity" after Andrew gets his lip waxed, ending up looking like a cross between E.T. and a naked mole rat.
- When Nick tries to kill Rick at the behest of his single pube, Rick's neck starts leaking pus.
- Jay pees in the Glouberman's pool for half an hour, which he attributes to drinking pool water.
- Jay mentioning that his kitchen sink is his "designated toilet."
- Andrew's Imagine Spot over the "Blue Waffle" myth may have coloured all of the gory stuff blue, but it's no less disgusting to look at.
- When Andrew sees that Lola has a lot in common with his dad, he starts imagining that Lola is his dad dressed like a 13-year-old girl, all the while "she's" being physically affectionate with him.
- The pool in Guy Town is infested with penis-worms.
- Cherry and Andrew's relationship as a whole.
- This leads to Andrew practicing the right type of dick pic with Maury to send to her, meaning more pictures of his dick.
- Jay having the power to manipulate his semen, à la Avatar: The Last Airbender.
- The dirty diaper fight Steve and Jay got into when Queer Eye visited them.
- In "Super Mouth", Andrew's invisibility is triggered by him farting on command. At one point, one of his farts are so potent that it actually causes Maury's eyes to water and him sweating. He settles for laying down.
- And since turning invisible involves getting nude... well, you know the drill.
- Jessi wakes up in a puddle of her own menstrual blood. She tries to mitigate this with a maxi-pad, but it comes off once she goes swimming in the lake and absorbs all the water.
- Nick gets barfed on twice and then has a kid piss blood on him when he tries to take a shower. And then he walks around with the stench all day because he was too scared to shower with Andrew and Seth.
- Andrew's constipation. The pent-up crap grows and takes on a life of its own, tormenting Andrew and telling him it plans to assimilate him.
- Michael Angelo's blue balls exploding blue liquid onto Connie and Jessi during "Four Stories About Hand Stuff".
- One of Andrews horror visions in Horrority House has his insides and genitals sucked out of his rectum after his butt gets stuck in an airplane window after its blown out.