I am pleased to announce that vagina tattoos are officially mainstream, with a how-to video on YouTube and blog posts here, here, and here. Unfortunately, the internet keeps calling it a "vatoo," when the superior term is clearly "twattoo."
Now, I realize that twattoo practitioners have so far favored "vatoo," and everyone's probably using that term in deference to their expertise. But is "va" really enough to indicate "vagina"? Vatoo's predecessor, "vajazzle," includes that crucial soft-g consonant sound. "Twattoo," on the other hand, contains both "twat" and "tattoo" in their entirety. If someone shouted "Vatoo!" on a crowded street, you'd probably reply, "Gesundheit!" But if a lady sidled up to you at a bar and purred "Twattoo" in your ear, you'd know exactly what she meant.
"Twattoo" also allows you to sneak a naughty word into conversation without actually saying anything naughty. There are only so many conversations you can have about "Uranus," "pupu platters," and "Lake Titicaca," after all.