I think it’s definitely true that this society takes a man’s erection as consent. I also think that many men struggle to express themselves in the moment. The last situation you described seems like one which might have been avoided if he had felt empowered to insist verbally that she stop. I think men encounter many situations like this, in which they feel obligated to say yes or allow sex to occur. They then convince themselves this is normal, and treat women this way.

Which is why we should teach consent to everyone.