If she asks to play… you have to do it. If she doesn’t… you have to ask, because she needs to get tired, or you won’t be able to sleep tonight. At the end of the day — quite literally — you must play with her. She can be devastatingly exuberant.
I am sure it is no accident that most of the pictures of Dafne playing were shot with a Canon EOS 5D and its flash 430 EX II, because I do need to freeze the movement; while on the other hand I can very well use my iPhone for most of her sitting photographs (see here).