swing low, swing high

Children's play area at a music and arts festival. Evie does her usual thing of very quickly making friends with other random children.
She got together with this group and they shared a swing. The long haired older boy pushing it was, shall we say, enthusiastic in his work.
It was a bit terrifying to watch as his feet leapt off of the ground with effort. The best I could do was ensure she held on. I saw the fear in her smile, but just had to trust her when to say enough. She was torn between fear and wanting to be cool. And also, she did like it a bit. Eventually she did say 'not quite so high this time please' and he was perfectly reasonable about it. He had no malice, he just really really really loves pushing swings!