'There will be kissing': Meet the production team for the auditions of new Fringe show Lesbian Bathhouse

Nothing compares to the intensity of putting a Fringe show together. Everything from the number of stars on your review and the number of bums on your seats to the number of weather fronts in a day is about as predictable as the winner of a wet Grand National. This August, director Nigel Miles-Thomas and Fringe Management are betting on Lesbian Bathhouse, a play – described by the Chicago Reader newspaper as "sexy but never sweaty" – by New Yorker Helen Eisenbach involving seven lesbians and the disembodied voice of one man.

The male voice was a shoo-in and cast in New York – Harry Shearer, voice of Mr Burns and many others in The Simpsons. The seven lesbians were all, as it were, up for grabs. Miles-Thomas put out a casting call, which was answered by more than 1,000 twentysomething actresses. So it has been a tough few weeks for Miles-Thomas and producer Michael Blaha, but somehow they managed and now there are just a couple of dozen left in the running.

Now before anyone asks what two heterosexual men are doing casting a lesbian play, let me reassure you. For starters, this is no ordinary "lesbian play", it is a terrific piece of comic writing, set deep in home truth, with a ruthless New York smartness that makes you laugh out loud. Also, not only (and unusually) did Miles-Thomas bring playwright Helen Eisenbach in on the auditions, but he even engaged the expertise of a second female with expertise not only in theatre, but also in lesbians. That would be me, by the way.

Day One and we are in an atmospheric attic above The Rag House, a new "creative" space off London's Brick Lane. I am greeted by someone who introduces himself as "a Welsh poof" in search of a kettle. He is Ben, assistant director, script-reading stand-in and, today, teaboy. Nigel, Michael and Helen are gently backlit by the grey light coming in a broken window. Auditioning, someone once said, is like having sex with someone for the first time: you are usually appalled by your performance and don't expect to hear from them ever again. Even being an auditioner the metaphor still holds true. And we have so many women to kick out of bed.

As each wannabe girl's girl arrives, my gaydar notes with interest that almost none of them is likely to know the words even to the chorus of Constant Craving. I wonder if this matters. It doesn't seem to matter to Eisenbach, a tiny, warm, don't-let-the-blonde-curls-fool-you New Yorker who once described herself as a "womaniser" rather than a "lesbian" and who has written for both the New York Times and The New Yorker as well as creating a helpful tome called Lesbianism Made Easy. She wrote the play originally to cheer up a friend who had just found out the hard way that lesbianism isn't in fact easy. Apparently there was a great deal of "orientation shift" during the first production. The semi-straight cast were all a bit hesitant when they arrived, she says, and she let things "happen at their own pace". After a few days rehearsal "they were ripping the clothes off each other". One girl arrived straight and ended up having her heart broken by someone else in the cast.

Some auditionees bring props, another brings her mother. All are given the best possible chance. Occasionally Miles-Thomas offers some direction: "Play it as straight as possible," he suggests. "So to speak," murmurs Blaha.

After reading, the girls come and sit by us. In making sure the hopefuls have understood the tenor of the play, Miles-Thomas gives a fair impression of Derek Nimmo stranded in a Carry On film. "You know there will be …" he swallows "…a certain amount of…" he twizzles his pen. " There will be … kissing," he finishes, pinking boyishly. "I am just trying to be sensitive!" he hisses as a wannabe leaves and the rest of us giggle. By mid-afternoon we have progressed through reassurances that it will "all be well lit and tasteful" and "tactful" to "quite… physical". Ben leaps in to help. "There will be tongues," he declares to one amused young woman.

Most interestingly for me, with many of the girls when Nigel and Michael are in raptures, Helen and I are head-shaking. Again and again it happens. In the final reckoning, I discover, they not only listen but act upon what Helen says. By the end of day two we have all fallen in love at least twice, Nigel now remains a normal colour when he talks girl-on-girl, and I cannot wait to see this show.

Several weeks later I am e-mailed the results of the photo-shoot for the show's poster. The girls seem to have got over that "physical" thing with very little problem. And they've still got time to rehearse.

• Lesbian Bathhouse is at Assembly @ George Street, 5-29 August