From the looks of it, there was a fight and she got hurt too.
Likely, it didn't start out this way, with her on the advantage. She gained the upper hand at some point probably.
Judging by how angry she is, and how they're in the middle of sex, it might be a case of actual reverse rape. As in, he tried to rape her, she fought back, pinned his ass down, reversed it
Of course its just one possibility.
Could be this is just how they do things, or she doesn't like the guy, or he came too soon, or he told her he put on a comdom. lol