(Ron Charles/The Washington Post)

Scour the Internet all you want, but you’re not likely to find a more pleasant story about pornography than Tom Perrotta’s “Mrs. Fletcher.” It’s as well-behaved as “The Abstinence Teacher,” his 2007 novel about a public school sex-ed instructor.

(Scribner)

Which raises the question of when it’s bad to be good.

Perrotta is an affectionate comic writer, but to his own detriment, he has mastered the art of suburban titillation — and he rests on it. Although lusty subjects thrum through this novel, they’re often blanched. The effect can feel like reading the essays of Camille Paglia printed on slices of Wonder Bread.

One might have expected more from the author of “The Leftovers,” a dark, apocalyptic novel that Perrotta transformed into an even darker and more transgressive television series for HBO . But, alas, despite its sultry promise to examine the varieties of sexual experience, “Mrs. Fletcher” is a tightly corseted story.

The first few pages, it turns out, are just a fantastic tease: Eve, the Mrs. Fletcher of the title, happens to catch her son’s abusive dirty talk while he’s being fellated by his high school girlfriend. Eve is no prude — “when she went to the drugstore, she made a point of asking her son if he needed condoms” — but overhearing him in flagrante delicto makes her realize he’s developed some fairly boorish attitudes about women.

That climactic opening contains what Perrotta can do so well (including start a novel with a bang). As he demonstrated in “Joe College” and “Election,” he knows how to capture the hilarious contradictions of teenagers. Eve’s handsome son, Brendan, is a textbook breed of innocence and entitlement, strutting through the world with full arousal and assurance. And his girlfriend is a heartbreaking blend of naivete, desperation and expertise.

It’s Eve, though, who really gives this scene a charge. She’s about to drive Brendan to college for the first time when she accidentally eavesdrops on that nasty pillow talk. It “echoes through her brain on an endless loop,” prodding her to upbraid him during their final hours together. “She didn’t want him to begin college,” Perrotta writes, “without understanding that there was a fundamental difference between sexual relationships in real life and the soulless encounters he presumably watched on the internet.” On the other hand, she doesn’t want to spoil her last day with her son. Throughout this wincingly awkward opening, Perrotta captures the strained embarrassment that courses like electricity through his suburban America.

But “Mrs. Fletcher” soon loses that vibrancy when the narrative splits to follow the competing sexual adventures of Eve at home and her son at school. In the libidinous groves of academe, Brendan finds his romantic thrusts blunted by women more sophisticated, enlightened and aggressive than his pliant high school sweetheart. And yet his story never develops the psychological depth or satiric edge to make these scenes sufficiently moving, witty or arresting.

Author Tom Perrotta (Ben King/HBO)

Which is odd. After all, the sexual antics of the modern-day campus offer such fertile ground for a social novelist — everyone from Tom Wolfe to Bret Easton Ellis has drunk that up — but Perrotta remains disappointingly demure. It’s not just that Brendan’s experience is familiar, it’s that Perrotta seems unwilling to say anything particularly penetrating about the complications of college sex in an era of wildly fluid mores.

Back home, the novel’s exploration of Eve’s romantic life is more promising. Abandoned by her husband and now her only child, Eve fears her life has turned into “this lifeless hush, this faint but elusive whiff of decay.” Attractive and still in her 40s, she works at a senior center where the residents are starting to look like ghosts of her future. Hoping to “reconnect with her collegiate self,” she signs up for a class called “Gender and Society” taught by a transgender professor. The course gives Perrotta an excuse to include potted discussions of sexual theory, while the professor’s assignments ask Eve and her fellow students to “write autobiographically and analytically about their own problematic experiences on the gender spectrum, with special emphasis on the social construction of identity.”

Perrotta sets up a clever tension between that academic theory and Eve’s rapidly broadening experience. Soon, she’s spending her evenings surfing the cornucopia of online porn with a mixture of anthropological curiosity and sexual arousal. Most of the lurid sites do nothing for her, but every once in awhile she clicks on a couple of actors who seem genuinely inspired. “Maybe for a minute or two you’d feel that you were right there with them,” Eve thinks, “like when you heard a good song on the radio and the next thing you knew you were singing along.”

That amusing tone is enough to sustain the novel for a while, but soon, like lonely, frustrated Eve, we want something more real, something more complicated. Having jumped into this vast ocean of id, Perrotta presents sexual anxiety attenuated to just another suburban concern, something on the order of “Should I get that tree branch trimmed?” Without a more discerning narrative voice and a greater willingness to explore the complexity of desire, there’s nothing to disturb the comfortable patter of “Mrs. Fletcher.” The novel hovers awkwardly between farce and psychological realism. Its neat checklist of sexual experiences — Lesbians! MILFs! Three-ways! — starts to feel like a weird session of Wednesday night bingo.

Safe sex is all good, but safe writing about sex is just going through the motions.

Ron Charles is the editor of Book World and host of totallyhipvideobookreview.com.

On Thursday, Aug. 10 at 7 p.m., Tom Perrotta will be at Politics & Prose Bookstore, 5015 Connecticut Ave. NW.

Mrs. Fletcher

By Tom Perrotta

Scribner. 320 pp. $26