It's a good thing she agrees, because Jaskier is just on the edge of petulant, to insist this is, actually, quite unfair -- that she should know all of these things, these effects, that a vampire's bit could have, and not let him have even a hint of it.

Though it makes him wonder if the one she learned this from... if they shared it, personally, with her. A story to ask her when she is delightfully naked later, he thinks.

For now, this is distraction enough. Jaskier has enough experience he has a sense for when he's getting his way, and he can see it in her eyes that she's agreeing. Agreeing this is cruel. So he keeps his hand where it is as she decides.

It is rather good she suggested the bite would have an effect, as he isn't entirely sure what to be prepared for. Not the jolt from his hand, or the cool comparison of hers; not the shock that fires down his body, a rush of warmth blood leaving his head heady and his body in rapt attention. She sucks, and another drop of blood rolls down his thumb.

And that was only a finger.

"Oh."

Oh, this is a most excellent surprise.