Alternatively, maybe the user is referring to a phrase like "it up the ass" in a slang context, but that might be offensive or inappropriate. I should consider that the user might be using the term in a non-literal way or perhaps in a title. Also, "vol" and "full" could refer to "volume" and "full", maybe as in a book or film title like "Vol. 1: Full Circle". But the user included "private+innocent+teens+love+it+up+the+ass+vol+full". Maybe they're looking for an academic paper topic that somehow connects all these terms appropriately.