I'm halfway through watching this but came to IMDb to see if the children were related. As someone who grew up with a similar age/gender dynamic with my 3 siblings this felt very familiar, casting a real life family was a brilliant move. It brought a depth and authenticity to the relationships in this film, far more nuanced than what would have been achieved with actors this young, had they not been related. The little penis song was too adorable. Very clever idea for a film, not something to watch if you need explosive action to enjoy a film, but if you like intensive intimacy then this is a great choice. The colour tone was really nice too. I had to turn my brightness up but I think it set the tone well.