I have a 4 year old and a 19 month old. The 19 month old often wants to play with his sister, he loves playing with other people. My 4 year old though cannot adapt her play to include him, and gets very stressed and upset (today we were dancing, she had a very long ribbon she was twirling, he caught held of the other end and shook it too and giggled, she cried and shouted at him and the fun stopped.) She will play with him if she's in control and he's doing what she wants, but as soon as he tries to deviate from her plan she gets upset, instead of going along with it or negotiating. I've tried showing her ways to let him join in, initiating games wgetectheybcan both play, I do distract him and let her play with something alone pretty often too as I know she doesn't have to share everything. I admit I feel a bit lost with this too as I was an only child and also very set in my ways, so I can understand how she feels. Any advice to help me to encourage her to play more flexibly with him?