(He isn't going to do it.)
Lilómiel. She needed Lilómiel. Come back.

Then a growl rips through the air, angry, harried, furious. Her heart pounds a fearful beat; her blood rattles through her veins. It takes a moment for his words—no, word—to register: no, resonant and resolute. If she had the time, she would dissect his refusal. Determine the exact nuances of his no. Decide if it was her or... her (was it because she was his twin? Or was it because she wasn't pretty enough, wasn't beautiful enough?) A wave of shame overrides rationality, shame tailed by disgust.

Disgust at him. Disgust at herself. And anger. It hadn't worked. When did she ever fail with Volterra? (It was final. He was a threat, not a friend.)

She doesn't know what face to wear for him, so she wears no face at all as she pivots on her haunches to look in his eyes. (Red on red. Both of them angry.) Nym's eyes flicker to his haunches boner, and then back to his white-marked face. Another wave of disgust; another wave of dismay. There was too many emotions vying for her attention. Instead of following any one of them, she ignores them all. She stares at her brother. Stares at his strange face.

Subconsciously she picks at his voice. It is unexpectedly soft, edged with lust and sharpened with something dark and venomous. It doesn't help her.

You need to stall.

“I—” she starts, and then she blinks, falling silent. The silence draws thick between them (perhaps awkward for once in their life.) What do I say? Because in some way it was true. She knew she could never be intimate with Volterra in the way others were (this moment had proved it more than anything) and she was... jealous, envious of their ability to have his children and capture his attention. To Volterra she'd always be a sister, nothing more and nothing less; and to her... it wasn't enough.

She breathes out low and slow. When she speaks, her voice is empty of any marker of emotion.  
"It's wrong but you wanted it anyway. You're an animal Volterra."

Then Lilómiel's here, approaching from behind Volterra towards Nymeria.  

Now.

Black jaws part and flame pours from between white teeth, aiming at Volterra's haunches; then the dragon dips low, shifting his aim to Volterra's family jewels. Nym backs away hastily, and at the same time wrenched at Volterra's blood, attempting to draw it free from his orifices. She was counting on him being distracted (by flame and by pain), counting on him rushing for the river; and then, without another word, she turned and trotted away with a final swish of her tail towards home.