HOLD on to your laps, Amer ica. And lock up the kids until they’re 42.

The latest addition to the well-stocked smut canon is aimed not at adults, but at impressionable teens and pre-adolescents. It’s called “Castration Celebration” — a kind of “High School Musical” meets “Saw.” Gross.

The novel is about what you think, but worse. This twisted, comic romp does little more than cheerfully promote underage sex, drug-taking, binge-drinking and, most painfully of all, male dismemberment by a high-school-age female, the heroine.

The theme is captured on the very first page, which reads: “Did you know that in imperial China, eunuchs had their testicles, penis [sic] and scrotum [sic] removed?”

Aside from the egregious grammatical sins, the nastiest thing about this book is that it’s not offered for sale in a brown paper bag by some oily character. This tome is the giddy, proud publication of prestigious Random House.

Random House Children’s Books, that is.

Believe me, I’m not so naive as to think kids don’t engage in some of the acts listed here: Sex. Gay sex. Drunken sex. Stoned sex. Angry sex. Unprotected sex. Sex, real or imagined, with farm animals. Baaa!

But, really, Random Partner House, are you in the business of publishing how-to books influencing youngsters?

The main character is Olivia. who is traumatized after catching her father in flagrante with a student not much older than she. Her pathetic mother cries. Olivia, meanwhile, searches for a sharp pair of scissors with which to punish Max, a high-school boy crush who punishes her by screwing a drunk, older girl.

Castration fantasies run throughout. “You know what would be cool?” Olivia says. “You know how toy stores have doctor kits for kids to play with? What if they sold miniature castration kits?”

Later, Max finds his way back into 17-year-old Olivia’s bed by vowing, to his mother, to cut it off.

Males, all males, are presented here as loathsome, filthy and out of control.

The author is Jake Wizner, a man and a Manhattan middle-school teacher, which gives me the creeps. “A lot of 14- to 15-year-old boys don’t like to read a lot. But the stuff I’m writing speaks to them,” he said. However, Wizner said that while he would not assign this book to his own eighth-graders, he would not take it away either.

What bothers me is the way aberrant behavior — drug abuse, blotto drinking, compulsive sex — is normalized. These activities are treated as routine, things not to be condemned, discouraged, or even reluctantly tolerated, but celebrated. Like castration.

Wizner’s biography lists his hobbies as writing, teaching and “going to the playground.”

Just not near my kid.

andrea.peyser@nypost.com