If men would take women more seriously -- in and out of bed -- they could eliminate most of their own sexual problems, contends former California and Michigan sex counselor Michael Castleman.

Women, he says, want "leisurely, playful, whole-body lovemaking," instead, they too often get haste, mates who aspire to be "tough, icy and domineering" and who treat them as "chicks" or "playthings." Castleman, in other words, is telling men to listen more closely to their partners -- not just for the woman's sake, but for their own.

One of the founders in 1975 of the San Francisco Men's Reproductive Health Clinic, the first public health facility in the country to focus on men's birth control and sexual concerns, Castleman figures he has helped more than 1,000 men resolve their bedroom anxieties. He has detailed his philosophies and self-help therapies in a new book, Sexual Solutions (Simon and Schuster, 287 pages, $12.95), which the Playboy Adviser column calls "the best common-sense guide to sexual problems we've encountered."

Among Castleman's common-sense pronouncements: "As time spent in sensual loveplay increases, a man's likelihood of developing sex problems decreases." And women "get the sensual attention that is so important to them."

Castleman's California clients -- "I was astounded; they came in droves" -- ranged from teen-agers to men in their 70s, and included one septuagenarian who wondered if he was abnormal because he still enjoyed sex.

"These guys would come in really distraught. They would say, 'I'm going crazy.' It became a buzz word for sex problems. A lot of these guys were intelligent people," including a couple of doctors. "They're the guys who are supposed to know. They don't know.

"Many men gauge their masculinity by their ability to 'do it right,'" says Castleman. "If a man does not function in bed at the level he considers 'normal,' he may conclude that he is not a whole man -- if he ever was.

So much sex counseling, he says, "is telling people they don't have a sex problem." When they think they do, "they panic and suspend their good judgment." You let them know, "It's not hopeless. Not only not hopeless, but you can fix yourself up" -- alone or with a partner.

"Almost any man can learn to last as long as he would like," says Castleman, who believes that physical causes of involuntary ejaculation (he dislikes the usual term "premature ejaculation") "are extremely rare." One man he helped told him: "Hey, I can't believe it. I've had this problem for 15 years."

The two keys to lasting longer, he says, are reducing tension and becoming "more comfortable with your body's sensual responsiveness." To accomplish this, he advises a variety of techniques, ranging from deep breathing (to appear cool, "many men suppress the body's desire to breathe deeply during lovemaking") to masturbation. His success rate with clients, he says, was about 80 percent after several weekly counseling sessions.

Impotence -- "a more complicated problem -- generally has been considered mostly psychological. Castleman argues that other factors play a big part: physical illness; overuse of drugs, alcohol and tobacco; exposure to pesticides and industrial chemicals; and dietary deficiencies. Or it could be stress from a wide variety of sources -- an exhausting job, a quarrel with a mate.

Now 31, Castleman began working as a sex counselor in 1973 at a Free People'c Clinic in Ann Arbor, Mich. At the time, he admits frankly, he was experiencing a problem of his own, which he had decided was "hopeless."

But in doing some research -- "My mother's a librarian" -- he studied the techniques of Masters and Johnson and other sex therapists which he eventually adopted. "It sounded simple."

With the help of his girlfriend, now his wife (a family-practice doctor), he resolved his problem. "I was astounded how quickly, virtually in a week. And I had been freaked out about it for years."

Castleman began teaching the techniques he had learned to other Ann Arbor males. Word of the program spread, and a pamphlet displayed at the office, "You Can Last Longer," was "stolen so frequently we couldn't keep it in stock."

Later, when he headed the San Francisco clinic, the response was the same. He has since left the clinic to concentrate on writing about health issues and is currently managing editor of Medical Self-Care magazine.

Men who are having sex problems, he finds, tend to "retreat from sensuality" even though they may be "starved for affection and want somebody to cuddle up to. A lot of them say, 'I'm a flop. She can't love me.'" To get couples to begin talking over -- and doing something about -- the situation, he suggests they each write out a list of "what they want the other to do physically for them.

"The easiest things first," such as "more cuddling."

Says Castleman: "Lovers start to get practice in requesting things and the gratification that he (or she) is willing to do it. You make a good faith promise and take it seriously. Over a year or two, people get requests at a peace that allows intimacy."

Even today, "Most guys," says Castleman, "learn about sex the way I did -- at the curbside." Nine-year-olds learn from "the older guys," who are 11. By the time he's 16, "no man is going to admit 'I don't know everything about it.' They're stuck with misinformation for the rest of their lives.

"Who among us receives any formal training in the sensual art of making love?"

The men's magazines and pornography exacerbate a male's anxieties, he believes, by creating "sexploit" images few can match. "The big lie," he calls it. "You feel that unless you've got your fly unzipped six hours a day, you're abnormal." They also help maintain the macho myth -- "that the man is the aggressor, the dominant one and the woman submits.

"Men who try to be sexual superstars often find themselves on a one-way trip to many of the sex problems that can turn love-making into a nightmare."