I challenge you to watch this without the sound. It looks like two people having sex.
Cersei knew exactly what she was doing here. The only time she really pulls away is when she gets grossed out by his lack of a hand.
This is not blaming the victim. Are we really to believe that Cersei actually loses control of him here? That she doesn’t know exactly what to do or say to get him to stop? She knew he needed to feel in control, and she needs this in order to get him to do what she wants.
Perhaps a better choice of dialogue would have fixed it. But if you look at it in the light of it being part of Cersei’s crazy plan, it makes total sense.
Ultimately It was done too subtly, for sure. But he is not a rapist and she is a hateful woman. Nothing is ruined and I think that will be more than obvious next Sunday.