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.
Funny lady and apparently very experienced. The front of it is clear she developed a toy, but the anus is open by itself and quite ready for sex. Chic woman, except that the breasts are lopsided despite its rather modest size. The only question is, what position does she qualify for?
That nut's so good, it's worth a lick.