Eve has a little friend in the playground, M. He is 4 and his little bother is Eve's age. M is quite taken with Eve and Eve is rather taken with M. He is quite a boisterous little boy, but very gentle and kind to Eve. I think it might help that she is the same height as he is.
We were in the playground yesterday and the three of them were playing together. M needed a wee and ran over to the gutter, pulled down his pants, and had a wee. Eve, wanting to copy everything he does, then went over to the gutter and pulled down her knickers. Quickly running over to pull them up, I explained to her that girls have to wee on the toilet. She initially seemed suspicious, but after some reinforcement by M's nanny, Eve asked to go to the loo. There are loos in the swimming pool by the playground and M insisted on coming with us.
When we got there, however, Eve refused to let me pick her up and pop her on the loo and screamed that she wanted to wee standing up. She had a complete tantrum over it. I explained that girls can't wee standing up because boys have a willy and girls don't. She started to scream louder. Whereupon I looked next to me to see that M had pulled out his willy, held it out so Eve and I could see and said proudly "see this is a willy, and you don't have one".
Eve went quiet, absorbed this piece of factual reality, turned around and sat on the loo.