First-Hand: She suddenly said 'I'm bisexual': Monique Roffey on the confusion of being chatted up, unexpectedly, by another woman

TWO IN the morning, and Miranda and I were alone sitting at opposite ends of the sofa. The other people who had come back with us from the restaurant were in other rooms or had gone home. We'd been chatting away, and naturally, as girly chats do, the conversation pulled round to sex.

'I'm bisexual,' she suddenly announced, looking deep into my eyes and casually letting her foot graze my ankle. A bolt out of the blue. If I'd had a drink in my hand I would have dropped it. If I'd had a mouthful of that drink in my mouth I would have sprayed it all over the sofa.

'Aren't you a dark horse]' I managed, smiling through frozen facial muscles. I'd had no previous inclination that this rather plump, blonde and Sloaney looking woman could be anything other than entirely heterosexual. Like me. I instantly sprang from my seat to go and fidget with the stereo an entire room's length away. Soon afterwards, I left.

On the way home, I felt pathetic. A bisexual woman makes a casual pass at another woman to test for possible mutual bisexual tendencies - and the woman almost implodes with awkwardness and embarrassment. But I'm afraid to say that I've handled every pass ever made towards me by a gay or bisexual woman just as gauchely. My encounter with Miranda is just one of several such encounters, and not - by far - the most embarrassing experience I ever had. That was the time four cocky young lesbians started making loud and lewd propositions towards me on an escalator ride up to the entrance of Camden Tube. I stood there, completely ill at ease and smiling stupidly, for what seemed like minutes while they made leery remarks and looked lecherously down at me. I said nothing and I did nothing because I simply didn't know what to do.

Lesbianism is very chic just now, according to magazines. Glamorous 'lipstick' lesbians are the most desirable guests at any fashionable party. But how are you supposed to react when another woman comes on to you, when she tells you, with a soft voice and soft eyes, that she thinks you're sexy? I know lesbian women often laugh about the stereotypical heterosexual woman who thinks all dykes fancy her. Well, I confess. I am that heterosexual stereotype. Gay women confuse me, and their advances, subtle or direct, are always disconcerting. I'm not gay or a swinger and nor are my friends. I'm a Catholic, 20-something heterosexual woman, and men fluster me sometimes. (Often). Let alone women.

Friends of mine agree. 'It's such unchartered territory,' says Frances. 'It's almost an impossible situation. You're not threatened physically, you're actually being paid a compliment, but you don't know how to say no.'

The problem is, that whereas we heteros find ourselves in these situations only on rare occasions, women who come on to you have generally had lots of practice. Looking back at the incident with Miranda, I suppose, if I'd been more alert, I could have read the signs earlier. I had been the focus of her attention throughout dinner. She had good timing. Telling me she was bisexual wasn't just a statement, but also an implied question - 'Are you?'

'Without realising it, you can be made the object of a seduction,' says Lara. 'If the woman is attractive it can definitely open something up. There's that element of temptation because you wonder what it would be like. Gay women must know the sense of wonder for straight women is there. When they make a play for a straight woman, they must know that it's intimidating.'

A sense of wonder, sure. All women check each other out. I like strong, intelligent and good-looking women. Most of my friends fit that description. I just know, very deep down, that my open admiration for other women is platonic. Completely non-sexual. I know that I will never want to kiss another woman's breasts. When the lights are turned down low, I know I don't want to be grappling with someone shaped just like me.

How do I know? I just know.