Hmmm well I've seen my boas lay their heads up onto things before and do what your girl looks to be doing (not very often though). Every time I'd wave my hand or snake hook around their heads they'd "snap" out of it and get all tongue flicky and interested. I'd keep an eye on her for the time being and have her quarantined: I wouldn't start worrying just yet personally. She's a new addition that may have some little quirks that you haven't come to notice yet.