Mary phones around 11.30am on Saturday to inquire if Wolverine's available to babysit next Friday night.
At odds as she is with most of the known universe, Wolverine is an inexplicably huge hit with little children.
Flattered by this adoration – a source of deep bewilderment to her harassed siblings – Wolverine has mentioned that she might consider being a paediatrician.
But despite the fact that the Mock Leaving is now only weeks away, she's still in bed, so there's no getting her to the phone to talk to Mary.
You promise you'll get Wolverine to ring her later, but Mary is an old hand at Wolverine management.
She'd rather confirm now, she says cautiously.
"Hang on," you say and trudge upstairs.
"Leave-me-alone-cantcha-see-I'm-knackered," mumbles Wolverine from a tangle of sheets.
Back at the phone, you assure Mary that your daughter will personally call to her home to confirm babysitting arrangements by tea-time today.
"Whaaat?" shrieks the Wolverine when she rolls out of bed just before lunch.
"You expect me to walk all the way to bloody Mary's house?"
"Well, yes, seeing as you wouldn't walk all the way downstairs to talk to her this morning," you say calmly.
Wolverine grumbles that she wants brunch.
"Go and do some work," you say through clenched teeth. "God," she says, "I really can't take all this endless nag-nag-nag about study."
Well get the hell out of my house and find yourself a badly paid job so, you feel like shouting.
But of course, you don't.
Having rejected everything your cupboards have to offer, Wolverine huffs off down to the village to treat herself to a chicken-and-stuffing roll in the smelly deli.
"Call in to Mary and organise that babysitting," you shout after her.
But when she arrives back at the house with the roll, a bag of grilled-steak- flavour crisps and a large Coke, she has not done so.
She's tired, she snarls; she's 18 and God, she so doesn't need your input here.
'But you can't leave Mary waiting for an answer," you protest.
"All you care about is appearances," says Wolverine inexplicably, and slopes upstairs.
Sixty-three minutes later, the day's study ostensibly done – at a conservative estimate, Fifteen, who is doing his Junior Certificate, works about three times as hard as her – Wolverine re-appears in the kitchen looking for a spin.
"A spin? Where?" you ask.
"Down to Mary's. You said I was to call in to her about babysitting," she replies.
Hands on hips, you shriek with hysterical laughter.
Wolverine stamps upstairs and holds tough.
But you hold tougher.