It wasn't only that it was a clear, breezy day in spring. Or that a lot of those present were sex educators, therapists and counselors and you would, after all, expect them to talk about what they did for a living. Or that there were some pretty explicit movies being viewed on the second floor of the Mayflower . . .

The American Association of Sex Educators, Counselors and Therapists began its 11th National Sex Institute yesterday, and it was more than friendly. Hovering in the air above the casual embraces and greetings of 1,000 participants were enticing snatches of conversation . . ."I bet he tried to seduce you . . . " "You would make a great subject for hypnosis. Have you ever tried it . . .""This is her second marriage . . .""Can we have a drink some time?"

On a plush, red couch in the corridor of the hotel, sat Shere Hite, best-selling author of "The Hite Report" and clearly the queen of the convention lin her pink ruffled blouse with its huge puffs on sleeves and flouncy brown skirt, cinched tightley at the waist. Surrounding her were men, one kneeling before her. "I told them to go get some chairs," she explained with a helpless little shrug, "but . . . "

But she was swamped with admirers. The minute one man would leave another would arrive to take his place - an Israeli pediatrician, two reporters a kneeling man who questioned her about the exclusion of homosexuality from her morning talk, and Richard A. Kaye, a very handsome professor of health education at Brooklyn's Kingsborough Community College who, in his blue-and brown-stripped ski jacket looked like a Playboy advertisement for a pipe.

"I'd like to see some studies on male multi-orgasmic phenomena," Kaye told Hite with great earnestness.

Hite said that she would, too. As it happens, she is now working on a book about male sexuality.

"Like you said," she told Kaye, there's not enough going on about it." Then she brightened and leaned over toward the health professor, "Want to give me your name and address, so I can send you my questionaire?"

She took out a tube of French lipstick and repaired her makeup.

The American Association of Sex Educators, Counselors and Therapists devotes a good portion of its time to the problems of standards, ethics and the certication of counsellors and therapists, according to its leaders. But there were times yesterday when some of the proceedings were curiously reminiscent of the bawdier jokes passed around at a stereotype salesmen's convention. As AASECT founder and executive director Pat Schiller made her way to the podium, she heard the words, "Pat, whenever I see you I get (aroused)."

Schiler grinned in response. She is, as she puts it, "a middle-aged lady with two children from Cleveland Park" who heads the human sexuality program at Howard medical school.

And she more or less began her opening speech by looking out over the large number of people assembled and announcing "Bigness is not necessarily better."

Schiller explained that it was she who was responsible for some of the snappier titles of the lectures given, from which we may conclude that "The Enslavement of the American Male: Success and Emotional Constriction," "Funny Things Said and Written by 8th Graders About Sex Therapy" all received the benefits of her inspiration.

Upstairs in the hotel, groups of very serious people watched "Sharing Orgasm: Communicatione Your Sexual Respones," a film in which a young woman wearing blue eye shadow begins potting a plant and then walks up to a man in purple shirt and takes his hand, saying "Steve, I got a new assignment - you know, from my sexuality group." At the end of the film Steve, who previously has been a bit wary of the whole thing, warms her heart by saying, "You know, it's not as bad as I thought it was going to be."

There also was a short called "Love Toads" which was, in fact, meant to be humorous, and featured two frogs in love, one red and one green.

Meanwhile, downstairs, Gloria Levitas, who is an anthropologist, created a bit of a stir by summing up her lecture on incest with "The family that sleeps together keeps together. That can be a good or bad thing. I take no moral stance." Which probably prompted Rabbi Balfour Brickner to conclude his incest speech with, "I still don't believe that everything that is done equals everything that ought to be done."

Nearby in a separate display room someone was selling a Love Swing, in champagne-coloured fake fur for only $44.95 ($5 cheaper than usual). And a decent reduction was being offered on the book, "Let's Make Sex a Household Word," which is down from $8.95 to only $5.