Girls got excited while riding stallions, so it's not surprising that when they saw those guys they jumped on them. Well, their chosen pose is exactly what I pointed out in the previous sentence. It has always been a mystery why so many girls love horses, actually this video partially answers this question.
It's an interesting camerawork solution, with the camera inserts that the guys are holding themselves. You look as if through their eyes at what is happening and very realistically imagine your dick in one of the holes of the slutty brunette, though the overall picture is not lost, and there's a lot to see here: a beautiful girl caught, skilled. And the guys are lucky, and us, the audience.
i want to fuck them