Well apparently very much wanted to fuck their mother, so he fucked their brother / son, I do not know what to call it, but judging by the moans from both sides they like this sex very much. Although in principle, why be surprised if the brother is such a yadda, then of course sex with him would have to both taste, and so it turned out. I'm surprised my dad didn't join in, because it happens all the time.
In fact, it's a proven fact. No one would refuse such a training session on boxing, see how she was furiously sucking his big dick, and she seems to be enjoying it as well. In general I think that such a fuck will be a norm for them now, because they are unlikely to stop at the received emotions, they will want more and more, and there more and more, we just have to watch.