[He isn't thrown off by her actions, and the desperation that drove her. All that he could wonder is what led to this; didn't they share in each other's blood just the other day? With how she is right now he would have guessed that it's been days, maybe even weeks since she last drank.
It really would be wise for them to at least get back inside. No one needs to see what is about to happen, no matter how little time (or the opposite) it may actually take. However, he lets Yuuki lead them. Unlike him, she has very little experience in forcing it all down. Even if it's now been a little while since he truly abstained.
Before she can go any further he tugs her down as he sinks to the ground and up against the tree. It'll give her more room, though more so will it lessen their difference in height.
One of his hands goes to the back of her head.]
It's okay, Yuuki. I'm right here.
[His reply gentle and reassuring while he holds her just as close. Of course it's okay. He tips his head a little more.]