“I haven’t used it yet,” I remind her. “Don’t get too excited.” I sit properly on the sofa and shift up a bit. “What are you watching?”

As I’m moving the cushions around, I see a book, nestled in Mum’s lap. It’s entitled How to Talk to Your Teens by Dr. Terence Kirshenberger.

“Oh my God.” I pick it up. “Mum, what is this?”

Mum flushes pink and grabs it.

“Nothing. Just some reading matter.”

“You don’t need a book to talk to us!” I flip through the pages and see lots of lame-looking cartoons, then turn to the back. “Twelve ninety-five? You spent twelve ninety-five on this? What does it say? I bet it says, ‘Your teenager is a person too.’ ”

“No, it says, ‘Give me my book back.’ ” Mum grabs the book before I can stop her and sits on it. “OK, now are we watching TV?”

She’s still pink, though, and looks kind of embarrassed. Poor Mum. I can’t believe she spent £12.95 on a book full of crap cartoons.

She read it! She read the £12.95 book!

The reason I know is that on Saturday she suddenly starts talking to Frank at breakfast like she’s speaking a foreign language.

“So, Frank, I noticed you left two wet towels on the floor of your bedroom yesterday,” she begins, in weird, calm tones. “That made me feel surprised. How did it make you feel?”

“Huh?” Frank stares at her.

“I think we could find a solution to the towel issue together,” Mum continues. “I think that could be a fun challenge.”

Frank looks at me, baffled, and I shrug.

“What do you think, Frank?” persists Mum. “If you were running this house, what would you advise about towels?”

“Dunno.” Frank looks a bit unnerved. “Use kitchen towel and chuck it away.”

I can tell Mum is a bit frustrated with that answer, but she keeps on smiling this weird smile.

“I hear you,” she says. “Interesting idea.”

“It’s not.” Frank looks at her suspiciously.

“Yes it is.”

“Mum, it’s a stupid idea I invented to piss you off. You can’t say ‘It’s interesting.’ ”

“I hear you.” Mum nods. “I hear you, Frank. I can see your point of view. It’s valid.”

“I don’t have a point of view!” Frank snaps. “And stop saying ‘I hear you.’ ”

“Mum read a book,” I tell him. “It’s called How to Talk to Your Teens.”

“Oh for fuck’s sake.” Frank rolls his eyes.

“Do not swear, young man!” Mum snaps straight out of her Stepford Mum mode.

“Oh, for futtsake!” chimes in Felix joyfully, and Mum inhales furiously.

“You see? You see what you did?”

“Well, stop talking to me like a bloody robot!” shouts Frank. “It’s totally fake.”

“Bloody robot!” echoes Felix.

“That book cost twelve ninety-five,” I tell Frank, who gives an incredulous laugh.

“Twelve ninety-five! I could write that book in four words. It would say ‘Stop patronizing your teenager.’ ”

There’s silence. I think Mum’s making an effort not to lose it. From the way she’s crushing her napkin into a tiny ball, I think she’s finding it quite hard. At last she looks up with a smile again.

“Frank, I understand you’re frustrated with life at the moment,” she says, in pleasant tones. “So I’ve found you some occupations. You can do some jamming with Dad today and next week you’re volunteering.”

“Volunteering?” Frank looks taken aback. “Like, building huts in Africa?”

“Making sandwiches for the Avonlea fete.”

Avonlea is the old people’s home in the next street. They have this fete every year and it’s quite fun. You know. For a thing in a garden with old people.

“Making sandwiches?” Frank looks aghast. “You’re joking.”

“I’ve volunteered our kitchen for the catering. We’re all going to help.”

“I’m not making bloody sandwiches.”

“I hear you,” says Mum. “But you are. And don’t swear.”

“I’m not.”

“I hear you, Frank,” says Mum implacably. “But you are.”

“Mum stop it, OK?”

“I hear you.”

“Stop it.”

“I hear you.”

“Stop it! Jesus!” Frank brings two fists to his head. “OK, I’ll make the bloody sandwiches! Now have you finished ruining my life?”