Spoon isn't a sane or normal person. Not even for werewolves. He's got testosterone where other men have common sense. On the other hand, he's got paternal instincts where other men have machismo (once you have killed a T-Rex, from the inside, with your teeth, you no longer need machismo).

Which is why he's not only willing to be leaned on, he's got that whole fatherly/older brotherly protective thing going. Yeah, he knows that under normal circumstances she could probably tie him into a half dozen knots within the span of five minutes. These ain't those.

And obsessively guardian animal has been used to describe him more than once.