Only seen the one episode. Not devoid of weird stuff (they are called "little sister games" for a reason), but I don't think anything is actually heading anywhere sexual. Doesn't seem to be that show.
....Just from my impressions so far.
As far as I can tell, its mostly going to a charming little series about a brother and grouchy little sister getting to know more about each other, while both get more in touch with their gentler side.
With a sub theme of "Get ya head outta the gutter, white boy."