I was going to take pictures, but who the hell cares, we all know what a watermelon looks like, and if you haven't seen a bottle of vodka.. well.. go look.
I cut a small hole in the watermelon, and started pouring in the vodka. It was hard at first, but then after the vodka started soaking in, it was quite easy. You just have to go slow, a tablespoon or so at a time until it soaks in. I used about a half a bottle of the medium Smirnoff bottles.
It tasted exactly like you would expect, except there is no "upfront" taste of liquor, just the aftertaste, which for me is the worse part.
All in all,
pretty horrible, but if you really like vodka, and you have a watermelon that you are not using, it would certainly keep a few alcoholic friends occupied for quite some time. It will confuse and amaze them that they can now eat their liquor, and it won't be half bad tastewise.
link for reference:
How to Make a Vodka Watermelon: 7 steps (with video) - wikiHow