My DD1 (5) is one of those kids who has to have at least the same as and preferably bigger than/more than her little sister (3.5) and on the whole at home I try to make them even of course. But there are always going to be some situations where they are treated differently, e.g. birthdays, preschool (they are in different groups) etc. and at such times DD1 goes ape and straight away starts hassling DD2 with "It'll be ours to share, right?", "If you don't let me have it I won't play with you", etc.
Yesterday the little one won the prize in her group for the best behaviour over the month - just 4 little fridge magnets, but straight away DD1 is molesting her: "Can you give me two and you have two?" "well, if you won't give me them I won't play with you" "I don't like you" and on and on until in the end DD2 said:"Oh, alright, you have them all" and just gave them to her. And she does it with a smile on her face, not begrudging her them at all.
This happens quite frequently, and I don't know how to deal with it. Of course I made DD1 say thank you and give DD2 a kiss but I kind of get the feeling that I'm allowing the wrong behaviour to be reinforced. What do you wise lot think??