Those who think it's not normal, think about it, these are strangers to each other. That's why there's nothing wrong with it. Two adults of different sexes are at home alone, hormones are splashing in both of them. So the skinny blonde was not at all against caresses from her stepbrother, she only broke down for show, but with his insistence his brother showed the seriousness of his intentions, and that this will not go beyond their bedroom. Both are happy at the end!
I think the video is just wonderfully thought out, because there are such immense asses, that you can't go without a big bolt, especially where double penetration, so you can see how she's enjoying her high spanking.