Well, in the story I got half-written it went like this:

A domme and her sub are in the kitchen. Like me, she enjoys cooking, so she's gathering stuff and having him do the drudge work of chopping and slicing. His mind is wandering and he accidently cuts her hand. It's a sharp knife so the cut bleeds profusely. He's horrified, she's stunned. Angry, she smears the blood in his face. She suddenly becomes aroused, but he's still horrified. She smears the blood on her face and pushes him onto the floor. She mounts him and rides him hard, cutting him with the knife to smear them both with his blood.

That's about as far as I got. It was pretty intense, and I wrote it in a stream of consciousness sort of style. Basically, he's turned on by her predatory attitude, but he's also terrified by this new side of her.