I took Penny to see my nana about three weeks after my birthday. I had conducted a series of careful briefings in advance, about the biscuit thing and any other potential pitfalls I could think of.

‘John! You’re taking me to your grandmother’s, not to a state banquet.’ Penny had said, after one of my panicky reminders on some trivial detail.

When we got there Nana opened the door as usual. I made the introductions and she clasped Penny’s hand between hers.

‘Pleased to meet you, love. John’s told me all about you.’

‘All good I hope,’ said Penny.

‘Oh yes, never a bad word.’ Nana glanced at me with a wink. She ushered us into the front room then said to Penny, ‘Will you help me with the tea, dear?’

‘Of course, Mrs Lazzard.’

‘Oh, call me Alice. We don’t stand on ceremony here.’ They headed off to the kitchen. I was left to admire the brasses, which I knew would have been given an extra special polish for our benefit.

They seemed to take a long time to arrange a few cups of tea but at last Nana returned, with Penny behind her carrying the tray.

‘I’ve got some of those biscuits you like,’ said Nana. I caught Penny’s eye and held it for a second in a conspiratorial glance.

We drank our tea and spent an hour or so in chit-chat. As I’d predicted Penny and Nana were two of a kind despite the sixty-odd-years age difference. At times I felt almost left out of the conversation, but I didn’t mind. There were no fears of lab rat experiments here.

When the time came to say goodbye at the door Nana said, ‘It’s been so nice to meet you, dear.’

‘It’s been lovely to meet you too, Alice,’ said Penny.

‘Make sure he brings you again soon.’

‘I will.’

‘Bye, Nana,’ I said and kissed her on the cheek.

We turned and waved from the end of the path. ‘I like your gran,’ said Penny as we walked away.

‘I knew you would,’ I replied, pride injecting a small spring into my stride. I wasn’t quite comfortable though, there was a question scrabbling away in my brain, like a puppy anxious to be let out into the garden. I had to open the door. ‘You were a long time in the kitchen.’ I tried to sound casual.

‘Girl talk,’ said Penny. Then she giggled.

‘What?’ I said.

‘She was asking me if I was on the pill.’

I blushed a deep, burning red and longed for the ground to open and swallow me up. ‘What did you say?’

‘I said no, but that when the time came we’d be sure to take precautions.’

‘Bloody hell!’ I was close to terminal embarrassment.

‘Don’t be such a prude. It was a perfectly sensible question. And it’s nice that she’s concerned.’

My mind switched to overdrive as I walked. I imagined the racy conversations that must take place at the over-sixties bingo. Then my cartoon devil piped up and reminded me of Penny’s words ‘when the time came’. He prodded me with his pitch fork and told me I was onto a certainty. I blushed harder still.

‘Do you do any other vegetable impressions, apart from beetroot?’ Penny asked, and we both laughed.

‘I do a good stick of rhubarb,’ I said, ‘but only in private.’

‘I’ve heard it’s more of a baby carrot,’ she teased.

I took the bait. ‘And how would you have heard that?’ Part of me was worried that the answer might involve Deborah Masters or Katie Simpson, and that maybe I’d regret asking the question.

‘It’s amazing what you learn when you’re a prefect.’ She adopted her moral superiority walk with her hands linked behind her back, like her dad, and her chin held high. I hadn’t been a prefect at school and she knew this would sting me almost as much as the carrot jibe.

‘So?’ I said, ‘I don’t remember genital inspections being part of a prefect’s duties.’

Her high moral expression collapsed into a smirk. ‘If I tell you, you’ve got to keep it secret.’

‘Cross my heart and hope to die,’ I said with earnestness borrowed from a passing nine-year-old. We had reached the square by now and were waiting to cross the road. She waited until we were safe on the other side before commencing the story.

‘You remember Bunny?’ she asked.

Now it was my turn to smirk. In the secondary school world of overactive hormones, spots and unscheduled erections, Michael Warren, known to everyone as Bunny, had more of all three than any other boy in our class. I had once accidentally ejaculated in a French lesson, having crossed my legs to hide a sudden swelling and squeezed the offending organ a little too hard between my thighs. The resulting mess in my underpants made me uncomfortable for the rest of the afternoon. How Bunny, who always sat at the back with his hands in his pockets and a smile on his erupting face, managed I didn’t like to think. No one liked to examine the front of his grey uniform slacks in too much detail.

‘How could I forget,’ I said.

‘Well, one day I was doing the lunchtime rounds with Andrea Patterson―’

‘Big Andrea.’ I grinned at the memory.

‘Don’t interrupt or I won’t tell you the story.’

‘Sorry, Miss,’ I replied, in a naughty schoolboy mumble.

‘I should think so,’ she smiled. ‘Anyway, we caught Bunny playing with himself behind the groundsman’s hut.’

‘No surprise there,’ I said, ‘he was always one for pocket billiards.’ One of the myths put about to discourage us from playing with ourselves was that you only had a fixed amount of semen to last your whole lifetime. We confidently expected Bunny to have run dry – or be in need of a white stick – by the time he left school.

‘But this was different,’ said Penny, ‘he was sitting on a steeplechase barrier, with his pants around his knees, giving it full wrist action.’ She paused as some people walked by. ‘He was so embarrassed I thought he was going to burst into tears. He pleaded with us not to turn him in, said he’d do anything, even let us stroke his thing.’

‘You didn’t?’

‘No! We said we wouldn’t go near his smelly little cock with a ten-foot pole.’ We had turned into Chapel Terrace now and she continued her narration. ‘But we agreed to let him go, on condition he told us who was packing what in their trousers. We figured someone who was always fiddling with his own tackle must check out other people’s in the showers.’ She smirked again before delivering her punch line. ‘And he put you firmly in the baby carrot category.’

I breathed a sigh of something close to relief. ‘I was always small for my age in fifth year,’ I said, ‘that’s why they never made me a prefect. And in any case, it was always cold in those showers.’

‘Time will tell,’ she grinned and returned to her moral high ground.

This was the strongest indication I’d had to date that sex was a real possibility. The cartoon devil was ecstatic and leapt up and down on my shoulder urging me to press for details.

‘About the precautions thing,’ I said, my mouth turning dry. ‘Do you want me to  …?’

‘Get something?’

‘Yeah, you know, blobs.’

‘Blobs,’ Penny sniggered. ‘Why do you call them that?’

‘It’s what I’ve always called them.’ I made a joke at my own expense. ‘With a name like mine I’m not going to say Johnnies, am I?’

We both laughed, and then she spoke the words that made my heart skip, my trousers swell, and the cartoon devil punch the air in glee. ‘Yes,’ she said, ‘we’d better be ready.’