The act of kissing someone's spine, lower back, or shoulder blades. It is to incite arousal and pleasure in the receiver, and, depending on the person, to make her feel as though he or she has been tickled.
when fucking a dry scratchy asshole with no lube, wrap one arm around the girl and brace the other arm across her back. Quickly jerk the arms together breaking her spine in two all while breaking the skin so that her spinal fluid leaks down the small of her back into her ass, thus giving you lube to wet up her dry butthole
this girls ass was so dry and i forgot to bring my lube, so i gave her a spinal tap and her spinal fluid worked like magic!