He rolls his jaw and concentrates, letting her touch him as she likes. But she'd asked him to teach her, and so he leans back in. "Keep writing, love." He sets down his own quill and wraps his left hand over hers. He shows her how to grip him, how to move up and down, where to squeeze. Where to pay extra attention. But this requires a level of coordination, when combined with his right hand beneath her skirt, he can't maintain. No matter; she seems to have the gist of it.