SLOW HAND edited by Michele Slung (HarperCollins: $20; 229 pp.) For those of you outside the Pointer Sisters' demographic reach, let me explain: The title refers to a fellow who takes his time in the sack, an appropriate enough reference for a collection of women's erotic fiction. Ms. Slung--whose other credits defy categorization, ranging, as they do, from a collection of stories about sex and horror to the trade-marked "Momilies" books--has collected women writers, some famous, some pseudonymous, all writing turn-on short stories. Slung's editorial comments precede each story, which is then followed by the author's note, an odd bit of fore- and afterplay, given what is sandwiched between, unless you happen to be aroused by an analytical description of what is about to occur. But a problem keeps coming up: Several writers equate ecstasy with surrender, which requires that a distinction be made between rape and ravishment, between the controlling fantasy and the uncontrolled reality of being out of control. Tricky business. Perhaps the best story is "Reasons Not to Go to Fort Lauderdale," a rather wacko examination of college-age lust. There are several candidates for the worst one, proving that women, unfortunately, can turn out just as many cliches (all in the name of enlightened sexuality) as men can.