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.
I may seem old-fashioned, but I love hairy pubes and I can't help it. I would have fucked that hairy juicy pussy myself, but the macho guy got ahead of me. Blonde in the body. She's got a lot to hold on to and a lot to stick in. And the way she screams with passion and rolls her eyes. You can tell she likes it on her dick. It's a young thing. With a hottie like that, you'll get a rock hard boner.)
Who's me as well?