Briefly, a full-package futanari is a person having a penis, testicles, and a vulva. Given no visible vulva, I've untagged this image. Check that wiki link I just gave you if you're confused.

As this is one of my favorite concepts in porn but one of the tags I most often see misapplied on Danbooru — by members of all levels — I'm going to make a habit of commenting about it every time I see it misapplied, because nothing else has worked.