Around her second birthday, my daughter was the cutie at the toddler group who loved passing toys to other kids. Fast forward six months and she no longer 'does' sharing. At a playgroup recently, she pushed away a baby from the trike she was riding.
Talk about mortified. Me, not her, obviously. She's oblivious to the chaos that ensues from instigating a tug-of-war over Sophie the Giraffe.
But she's not the only tiny snatcher.
'We once went to a toddler group where my daughter only wanted toys that other kids were playing with,' says Gemma.
'She snatched toys off other children and if they resisted, she hit them with it! When they lost interest and went on to the next toy, she stole that too. I was so embarrassed.'
Toddlers are ultra-possessive over stuff, aren't they? And it's not the case that this affects only children more than those with siblings. Young children simply don't understand sharing.
Take playdates. Let's face it, they just don't work with toddlers. Put two children in a playroom and it will end in tears because neither wants to go 50-50 on toys.
Or they both want to sit in the exact same seat. Or draw with the same wax crayon.
'My cousin left our house with her distressed two-year-old after a nightmare playdate,' says mum-of-two, Sara. 'My delightful three-year-old daughter snatched away anything that he tried to play with. Even the doorstop.'
'My son is nearly two and usually, he plays well with other children but when my friend brought her daughter over recently, he went into meltdown,' says Rachel. 'Every toy she picked up, my son would yell 'No!', then grab the toy and push her away and had a giant paddy if I intervened. I tried telling him off, explaining rationally that he had to share as well as distracting him with other toys. Nothing worked. I was so embarrassed.'
So is it possible to teach toddlers to share? And how can we smooth the way for harmonious playdates, rather than all-out war over the Duplo?
'Sharing is a lifelong skill, which we can start to introduce at the toddler stage, but it's tough,' says Joanne Mallon, author of 'Toddlers: An Instruction Manual: A Guide to Surviving the Years One to Four (Written by Parents, for Parents), published by Nell James Publishers. 'Other people's toys are always more interesting than your own.
'Expecting children to share their toys is a misnomer, because unless the toy can be physically split in two, what you're asking is for the child to give their toy to another child, when they're happily playing by themselves.'
And, put into context, perhaps their behaviour isn't so outrageous after all.
'What we're asking them to do involves an incredibly sophisticated thought process,' says Sarah Ockwell-Smith, author of 'ToddlerCalm: A guide for calmer toddlers and happier parents', published by Piatkus. 'We wouldn't expect them to ride a bike without stabilisers, at two, but that's what we expect them to do when we ask them to share.
'How would you feel if your neighbour came round and said: 'I want to use your car today so will you share it? You wouldn't be too happy. Well, that's how your toddler feels about the toy that they want to play with. Two-year-olds to four-year-olds don't feel empathy and can't grasp that they could upset other people by their behaviour.'
But, as parents, how do we handle the embarrassment when our little precious has a public meltdown over a Peppa Pig ball?
'Understand that it's not a reflection on you,' says Sarah Ockwell-Smith. 'Apologise to the other parent and say: 'It's tough that they don't understand sharing yet, isn't it?' Then tell your child: 'This little boy has been waiting a long time to play with this toy. Why don't we go and play with something else?'
'But if your child's in hysterics, it's about empathising with them. She's gutted that she wanted to play with a particular toy and it's now being taken away from her. If your child's hysterical, take them out of the situation.'
Before our first ever playdate, I envisaged a relaxed chat over a cuppa with the other mummy whilst our kids played peacefully at our feet.
Oh, HOW naïve.
The reality was my daughter sobbing in a corner, spread-eagled over a pile of her treasured toys, whilst her friend rooted, disappointed, through the near empty toy chest.
Hardly a relaxing morning.
Sarah Ockwell-Smith has a genius – if slightly expensive – tactic for more harmonious playdates.
'Whenever my own four children had friends over, I put their normal toys away and brought out toys that only came out for playdates,' she explains. 'I'd also ask the other mum to bring some of their child's own toys. But, inevitably, the children would want to play with the same toy and it would all end in tears.
'Really, we do playdates too young. Children don't play with each other until they're four. They parallel play until then. If it was up to them, they'd probably prefer not to have playdates. It's more a way for mums to get together and chat. We think that we should socialise children young but, until they develop social skills, it's hard.'
Joanne Mallon says that we need to be clear in our language so that our child knows what's expected of them.
'A really helpful technique is to count to five or 10 while your child plays, and explain that it'll be someone else's turn after that,' she says. 'Then count again whilst that child plays and make sure your child gets the toy back again when it's their turn. Children are often much happier to give something up temporarily if they know it's coming back.
'Watch out for times when your child shares well and give lots of praise and attention for this. Let them know when they get it right and they're more likely to do it again.'
But sharing goes both ways – and some kids will use it as an excuse to get even more grabby...
'I feel that telling toddlers to share in all circumstances can be counterproductive,' says Rachel. 'At a playgroup, my two-year-old son was playing with a toolkit when a girl came along and snatched the lot. He howled and ran after her, then the girl's gran came along. I stood back, assuming that Granny would give the toys back. Instead, she told my son that he had to learn to share, before presenting him with a solitary screwdriver. Cue meltdown.
'I'm all for asking politely to share but I don't like it when kids are taught to feel entitled to a share of something that someone else has.'
Of course, there are some situations when no amount of reasoning – or bribing – will get your little darling to part with whatever item they're obsessing over.
That's when radical action is required.
'When my younger daughter was a pre-schooler, she was used to everyone else saying 'OK, you can have it',' says mum-of-two, Vanessa. 'But after one playdate, when she refused to take off the ballet outfit she'd worn at her friend's house, my husband was determined not to give in to her. Which is why she eventually ended up being carried home naked!'
More on Parentdish: Tears, tantrums and terrible twos