This threesome isn't a crowd

To my surprise, she accepts the invitation with excitement and giggles as I hang up the phone. I'd be so disappointed now if she cancelled. The room is already booked and I can't bear the idea of having to snoop around Soho, probably at The Box, looking for someone suitable to join us.

Besides, a whole night of searching wouldn't provide us with anyone as beautiful as Helen. That's the thing about threesomes - they're rare because so many factors have to be right all at once.

All three people have to fancy each other; you can't be knackered; you can't have plates of half eaten meals and dirty socks all over your bed. The list goes on.

When the night arrives, I realise I'm dressing up more for Helen than for Neanderthal. It's almost like an exciting first date. I'm as careful choosing my undergarments as I am choosing my dress.

We've arranged to meet and have dinner first, around the corner from the hotel. Helen is already there when we arrive, reclining in one of the booths at the back, looking magnificent in a silver Fifties-style dress.

She is my perfect choice of third person. Not only is she stunning and a little naughty, she has met Neanderthal at least once before, which makes everything less awkward.

We have a good chuckle when she whips out a porn film called Vampiros Lesbos at the dinner table, and after lots of calamari we head for the hotel.

But when we arrive at the desk, the receptionist can't seem to find my reservation. As he rifles through papers shaking his head, I lean forward and whisper: "The Threesome Suite." "Aha," he nods, and promptly pulls my papers from the drawer.

"Is this the luckiest man in Soho?" Helen asks Neanderthal when we are all finally upstairs. He smiles in agreement.

It surprises me how much I love watching them together. It would be a completely different story if I weren't a part of it.

The Jacuzzi on the roof is open 24 hours so we decide to hop in and have a nightcap. The man from the desk walks past and gives us a knowing smile.

I smile back, content that there will be no lonely toothbrushes at the end of our night.