21/03/2012 17:36 GMT | Updated 22/05/2015 10:12 BST

Terrible Twos: Deal Or No Deal?

Terrible Twos: Deal or no deal? Playing swapsies with Pink

Other than the very impressive manoeuvre of stuffing an entire purloined fairy cake into her mouth before I can stop her (which she became proficient in ages ago), I think there's one skill that Ruby has nailed particularly early.

Because she has a big sister who is quicker and stronger, Ru often finds herself at the thinner end of the wedge when it comes to toys and the like. The answer, naturally, has been to master the art of negotiation.

I watched this in action a few days ago. Ava had gathered every single stuffed toy in the living room and had squeezed them down the back of the radiator with their heads poking out to make a 'bus'. She slowly went along the line, collecting their tickets and giving them some change.

Ruby was delighted for a little while, and she watched and giggled as Ava nodded and chatted to the floppy-headed passengers. But after a little while, and having been as patient as she could be, Ruby decided she wanted Bugger (her bear) back.

She went to take him – but it didn't make her very popular. Ava squealed: "Ruby! No! It's my bus!" and whisked the toy away to put him back into his 'seat'.

Ru's knee-jerk reaction was to cry, but she did so only briefly. She stood there for a few seconds, with her chin on her chest and her bottom lip sticking out. I was just about to intervene, when I saw Ru have an idea. She ran full pelt into the kitchen and opened (I could tell from her grunting) the big drawer of toys. Back she came, with a confident expression on her face, and a toy sword in her hands.

She offered it to Ava... who ignored her.

"Here go!" Ru said brightly as she poked Ava in the bum with it. Ava pretended she wasn't there. So Ruby dropped the sword and legged it back into the kitchen. Her next offering was a plum.

"Here go!" she said loudly and waved it in Ava's face.

"No thank you, Ruby!" Ava said, not looking at her sister. Ruby's arm dropped to her side. The plum dropped from her hand and rolled away.

Ru tried again. A Moomin book? No. A London A-Z? No. The scooter? No. A box?! She got inside it and tried, very obviously, to look like she was having a huge amount of fun. But no, it didn't work. Ava was busy driving.

Finally, Ruby had her eureka moment. She ambled casually around the living room (she should have been whistling) looking for something that she knew would seal the deal: Pink. She dragged it to Ava's end of the room, put it on the floor, then lay down and wrapped herself up in it.

"Ava! Ava, look!" Ru shouted and, when her big sister turned to see, Ruby rolled around, kicking her legs, getting herself ever more tangled in Ava's beloved security blanket.

"You're squashing my PINK! MY PIIIIINK!"

She had her. Ruby got up calmly, handed Pink back to Ava, and marched over to get Bugger. "Thank-oo!" she said, and smiled sweetly. Two seconds later, they both bombed out into the garden, with Bugger and Pink trailing behind, leaving yours truly to tidy up all the bus passengers and bargaining tools, and then scrabble around on the floor looking for a lost plum.

I love the way they work things out, but boy, they so do NOT get Mother's Day.