skin in the box Share definition Flag when you tuck the labia on an 'outy' vagina inside the hole, hence creating the 'skin in the box'. "damn, that chick had an outy, but i gave her a 'skin in the box' and fixed that." skin in the box by chodeman5000 August 19, 2008 0 0 Get merch Get the skin in the box mug. Buy Now — $32.95 See more merch