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."