Mary Roach goes all the way for scientific research.
In 2007, she had sex with her husband while a British doctor waved an ultrasound wand over their private parts testing their genital responses to the soundtrack of "Les Miserables."
Her compliant husband — innocently lured to London with the promise of "an all-expense paid trip" and a day at Stonehenge — rose to the occasion with a dose of Viagra, she says.
"It was a weird mix of medical procedure and sex," Roach, who took copious notes throughout, told ABCNEWS.com. "Ed said afterward, 'I was really creeped out that I did this.'"
It was all for the sake of Roach's new book — "Bonk: The Curious Coupling of Science and Sex" — which reached #10 on the New York Times bestseller list this spring.
"He's such a good person," Roach said of her husband, a graphic artist. "Mary needs this for her book, I will ejaculate."
Not since Masters and Johnson wrote "Human Sexual Response" in 1966 has the physiology of sex been explored in such detail. Until their groundbreaking study with married couples, researchers would "simply, quietly do it themselves."
In the case of London's Dr. Jing Deng, who studied Roach's sexual response, he wanted to capture "real-time, two-party human coitus," but he couldn't find takers. She volunteered.
"It's one of those things you agree to, and you're not really thinking it all the way through," said Roach. "If my husband had been thinking it through, he would have said, 'No!' The burden of performance was on him."
She even participated in an arousal study at the University of Texas at Austin. "It was not particularly demanding," Roach said. "I had to sit in a chair in a room with no pants on with a seismograph and was a control subject watching porn."
The 49-year-old is no stranger to strange topics. She has written about Eskimo food, flatulence, vaginal weight-lifting, carrot addiction and amputee bowling leagues. Her two previous books also explore oddities with humor: "Stiff: The Curious Lives of Human Cadavers" (2003) and "Spook: Science Tackles the Afterlife" (2005).
Curious is the operative word. Roach stuck her nose in a Taiwanese lab where penises culled from cadavers were skinned like snakes in an effort to find a cure for impotence. She also witnessed a Danish pig farm where sows were stimulated with vibrators to improve their conception rates.
Roach has discovered the term "boner" is also a misnomer. Unlike dogs and other mammals, men don't have penile bones. The walrus sports the largest one, and Inuits use it for war clubs.
It took Roach two years to research and write the book. "Sex is so intimate and personal and emotional, and science is so clinical," she said. "How you bring it into the lab and study it is a conundrum."
The daughter of a Dartmouth College professor and a secretary, Roach was raised in New Hampshire, where she "didn't quite fit in" at the local high school where most kids were "jocks."
She went to Wesleyan University in Connecticut, which has a reputation for open-minded inquiry. [At one time, the college was proud of its all-nude dorm.] "It gave me a kind of ridiculous hubris to do whatever I wanted," she said.
Roach's writing career began as a part-time PR person, working next to the Gorilla House at the San Francisco Zoo. Off hours, she wrote humor columns that appeared in national magazines and even on "The Colbert Report."
Her latest research proves to the reader that sex (at least when not a participant) can be either hilariously funny or disgusting.
She learned that man's closest relative, the chimp, has orgasms, and that nasal congestion is just "an erection of the nose."
While perusing patents, she discovered a stimulator for "partner-less" women: a box with an artificial penis and a furry cuff for "realistic effect." The device is more like "having sex with a shoe buffer," notes Roach.
Another failed idea was the "Penile Wrap," designed to heighten arousal with outfits such as a ghost, the grim reaper and a snowman.
Her dogged reporting uncovered the San Francisco Fire Department's short dial — "C ring" — for c**** ring emergencies. So frequent are such blunders that the city has practice drills and a small saw handy at all times.
She learned that back when perforated stamps were in circulation, men used the "postage stamp tumescence test" to see if their impotence was physiological or in their head. If a man can have an erection while he sleeps, thus breaking the perforation in the stamp roll, his equipment is working.
Roach takes a historical approach to her subject, from Leonardo DaVinci's work on cadavers left over from hangings to later studies that confirm that a dead man can, indeed, get an erection.
Marie Bonaparte, the great-grandniece of Napoleon, had her clitoris surgically relocated twice in the hopes of achieving sexual satisfaction. Her "rule of thumb" determined that the urethra and the clitoris should optimally be a half a thumb width apart.
Later research vindicated short, small breasted women everywhere, showing that they have better orgasms than "Barbie tall with Barbie big breasts," according to Roach.
Sexologist Kinsey — glorified in the 2004 film of the same name — pioneered modern sex research with his 1953 book, "Sexual Behavior in the Normal Female." He conducted (and participated) in furtive studies on a mattress laid out in his Indiana attic with willing friends of all sexual orientations.
He was an equal opportunity employer, recruiting gays, stutterers, amputees and paraplegics and those with cerebral palsy to his research efforts.
No gory detail is spared: Kinsey is filmed putting a swizzle stick and even a toothbrush (bristle end first) up his member while masturbating. Other masochistic types have been documented using a corsage pin, a Christmas tree twig and a rat's tail.
But despite centuries of fascination with how the biology works, scientists still can't resolve the "suck-up" theory, she writes. Do the muscular contractions of the vagina serve to enhance conception or are they "extraneous," like male nipples.
"No one can agree," said Roach. "It didn't evolve to make women like sex more. But you tend to think most things are there for a reason and conception makes sense."
But lab studies can only go so far. "There is a whole side of sex you can't bring into the lab," said Roach. "The emotional side is difficult. Arousal and orgasm are independent of emotional attachment and feeling."
While going the full nine yards has helped Roach's book research, it had some unexpected effects on her own sex life.
"When you get past the jargon, you have a new awareness of all things in your body and become a scientist in your own bedroom, and that can be really distracting," said Roach. "I found it annoying. Oh, what is happening, are my ear lobes swelling? It takes you out of the moment."
"But that was only a brief phase," she said. "Aside from that, we're talking about sex constantly and that is always a positive thing for your sex life."