What an ill-mannered daughter, how dare she behave like that in front of her father! No wonder he decided to punish her and pull her on his dick. It's worth giving this girl credit - both her figure and face are beautiful, but her behavior and character, there's a problem with that. Her father should punish her more often.
Well, half-brothers and half-sisters are not related at all, so it can't be considered something bad or immoral. It's no surprise that an adult guy and girl, with no regular sexual partners and almost daily being around each other, suddenly felt attracted on a sexual level to each other. Considering that the girl liked it (the guy then no question), I think they will continue to practice this kind of thing from time to time.