It's a terrible idea to inscribe that or anything else on your penis, and a worse idea to sext a picture of it to someone you're not sure wants to see it, but it's only a crime if a statute makes it a crime, and Warren was prosecuted under a Georgia criminal statute barring "Distribution of Material Depicting Nudity or Sexual Conduct" without a warning in "8-point boldface type."
The Georgia Supreme Court said the statute didn't apply to texting because it doesn't have "a tangible envelope or container on which the notice can be imprinted" and because texting wasn't a form of communication that existed back in 1970 when the statute was written.
I had some questions about penis tattoos, and I found this FAQ, which I recommend reading because it's informative — it answered my main question, at #4 — and funny — check out #5 "Design Ideas":
Whimisical [sic] and funny penis tattoo ideas include a Hammerhead shark, a pencil, a mushroom, a wad of money to blow, colored flames, Pinnochio [sic], or an arrow. More obvious animal tattoo choices for this area include fire-breathing and dangerous dragons, a sinful snake, or a grand elephant's trunk.Why is "funny" a good idea for your penis?! That quote has too many adjectives anyway. What's with "fire-breathing and dangerous" for dragons? It's like they're trying to nudge the reader to remember what the hell a dragon is. Why a "grand elephant's trunk"? I know there's good reason to assume the reader is dumb, but who doesn't realize an elephant is large.
As for a "sinful snake"... that's just sad. It reminds me of all the old ads for chocolate desserts that call the product "sinful." Those ads are directed a women, virtually exclusively. Maybe this FAQ is too. (Note: It's at About.com and picture-free.) Maybe these "Design Ideas" are just ideas for things to talk about with a naked man, not things for a man actually to tattoo on his penis.