Willow and I play this a lot, I surrender my hand to her and she lunges and chomps me in very light chomps. She *looks* aggressive, but she never is. Sometimes when I stop and begin to retreat, she grabs me and pulls me back in, as if to say, "more more". Normally when I invite her to come out onto my shoulder, she's eager. In this video, however, it was late morning and she had just finished arranging her nest; so, at the end of this video she declines my invitation to come out and shoulder hang with me.
Oh, and that cage level where she is? She stuffs it to the brim with paper shreds, coffee filters, and tissue paper. She has built up an entire cage structure. :)