We fall on to the bed and there are drunken hands everywhere running all over each other’s body. It’s not the most co-ordinated of efforts but there’s a kind of hot and heavy panting that comes from a lot of lust.

‘The costume,’ I pant.

‘Gotcha,’ says Max and he starts to wrestle the top, but it won’t budge. We sit upright and he gives the zip at the back another tug, but it’s stuck.

‘Hang on, let me have a go,’ I say and I put my arms round at the back, just as Max bends down to have a better look, and I whack him in the face with my elbow.

‘Ow, fuck,’ he says, cradling his eye.

‘Shit. Let me see, hold still,’ I say, leaping up.

He’s clutching at his face so tightly that I have to prise his fingers away to make sure there’s no blood spurting out of anywhere.

‘It doesn’t look like it’s bleeding,’ I say.

‘It fucking hurts, though.’

‘And your eye’s still there; that’s a good sign, right?’

I curse my Wonder Woman costume. I have dreamt about this moment for years and years and the one time I get Max in my bedroom I accidentally assault him.

‘I’ll go and get you some peas, OK? Stop the swelling.’

I hurry into the kitchen, find half a bag of peas and wrap them in a tea towel.

I make it back into my bedroom in record time but Max is passed out on the bed. Oh shit. I can feel my heart racing in a completely different way; now it’s in a sheer terror – what if he’s got a concussion?

I bend over to him to check his breathing and he’s lightly snoring. Do people snore if they’ve got a concussion? The clock on my desk reads 3.32 a.m.; it’s the kind of ridiculous situation where I’d usually phone Rach for advice, but I don’t think it’s quite the time to broach the subject of what I was doing in bed with her brother.

In a panic I go back into the kitchen and fill up a glass of water and I rush back to Max. I check his vital signs once more before I tip the water over his head, wincing as I do it.

‘What the…’ he shouts, sitting bolt upright and shaking the water off his face and out of his hair.

‘Oh, thank goodness,’ I say. ‘I thought you had concussion.’

‘No, I’m just drunk,’ he says, and he reaches out his hands and pulls me in, wrapping his soggy arms around me. He nuzzles into the back of my neck and goes back to sleep.