Acnestis: the section of an animal's skin that it cannot reach in order to scratch itself
Accismus: a form of irony in which a person feigns indifference to or pretends to refuse something he or she desires
Acnestis Accismus is pretending that you don't want to scratch that particular itch that bothers you (metaphorically). Often it is this way because the longing is considered odd or unachievable.