It was gratifying to watch BoJack Horseman become the most beloved talking equine since Mr. Ed. But there are a number of other irreverent animated series in the streaming galaxy that deserve just as much attention. “Big Mouth” belongs at the top of the list.

Since its premiere in 2017, the cartoon has been promoted as an honest, graphic exploration of puberty — the ultimate horror show. Its protagonists, their heads so oversized it’s a wonder they don’t topple over, have struggled with budding sexual desires as if they were tenderfoots heading to war. Their only support group: an army of Hormone Monsters who worship at the altar of Larry Flynt.

But Season 4, now streaming on Netflix, is the best evidence yet that the show’s creators aren’t playing child therapists. They’re focused on very adult fears, most notably the one about dying alone with nothing to their name except a paid subscription to PornHub.

The first new episode picks up where we left off, with buddies Nick (Nick Kroll) and Andrew (John Mulaney) at odds over their mutual affections for the same girl.

At least that’s what they say. What really concerns them — and has made Andrew unable to complete a bowel movement throughout most of summer camp — is the fear of losing your best friend.

Abandonment issues are also on the mind of Jessi (Jessi Klein), a child of divorce who is convinced her dad doesn’t want to spend time with her anymore.

“You’re like one of those stained mattresses left out on the sidewalk,” says one of her imaginary mentors, Depression Kitty, voiced with purr-fect sensuality by Jean Smart.

Missy (Jenny Slate) feels she might end up being tossed aside by her entire race because she isn’t “Black enough.” Matthew (Andrew Rannells) struggles to make a connection with his mom who hasn’t fully accepted that he’s gay. Even the Hormone Monsters worry about being ignored. In one scene, they complain they weren’t featured enough in the previous episode.

Near the end of the season, Nick must confront his adult self, a superficial game show host who would rather get his kicks from orgasm-stimulating pills than the warmth of another human. When eighth-grade Nick is separated from his body and floats above the jerk version of himself, his “counselor” explains what he’s experiencing.

“You’re a disembodied spirit,” says the Ghost of Duke Ellington. “Part of your soul is dead. Like Mark Zuckerberg.”

The Facebook founder isn’t the only figure or trend that takes it on the chin. John Oliver pops up to parody himself, as do the stars of “Pen15,” another terrific series that uses puberty as a platform for deeper issues.

“Mouth” producers even hold themselves to task. The show took some heat, and rightly so, for casting Slate to voice a Black character. The series remedies this decision by the end of the season, but not before giving itself a spanking.

Despite the heavy subtext, “Mouth” can also be a whole lot of goofy fun. The musical numbers, which include a breakdown on code-switching, are as clever and catchy as anything coming out of Broadway. For an added treat, try identifying the famous voices behind some of the guest characters. Hey, that summer camper sounds just like Seth Rogen!

You can see why so many A-listers have signed up. “Mouth” may star a bunch of kids, but it may also be the most grown-up party on TV. Twitter: @nealjustin