Nothing says "sexy" like an eye-patch, unless you need to wear the eye-patch because your eyeball is shooting out pus. I'm Hank Green, and this week on SciShow news: What science can teach us about sex and the human eyeball. You're the Internet, so you might have heard about this already, but teenagers in Japan have recently begun indulging in an expression of physical affection that I myself have never attempted nor have the urge to attempt. Eyeball...licking. Known as "worming", the practice has been described as a fad among teens who see it as a supposedly safe way to get freaky. Somewhere between second base and...I have no idea where. Much of the non-teenage world began to catch on to it just a few months ago when adults in Japan started noticing a bizarre fashion trend: lots of teenagers were wearing eye-patches. Nothing suspicious about that, right? But then earlier this month a Japanese media outlet reported that in one Japanese middle school a third of the students had been worming. Worming. Yes, why did they call it that? So those eye-patches that everyone was wearing? Turns out they were covering up pink eye,or conjunctivitis, an inflammation of the membrane that lines the insides of your eyelids and the whites of your eyes. Worming was causing an epidemic of eye infections. Now it's worth mentioning here that Japanese kids did not invent worming; there's a really weird passage in Nabokov's novel "Lolita" that depicts an act of eye love. And any old YouTube search, if you feel like doing that, will yield a number of eyeball-licking videos. This latest fad seems to have been driven by a music video from the emo band "Born", which features a woman licking the lead singer's eyeball, but then he gets disconcerted and then rubs his eye because, you know, gross. Physiologically speaking, there doesn't seem to be anything inherently erogenous about eye-tongue stimulation, but, you know, a lot of what is sexy is in the mind rather than the body. The problem with worming, though, is that even though there aren't really technically any "naughty bits" involved is that it is not what you would call "safe". Your mouth, and mine, and everyone's mouth, even in the best of circumstances, is one of the most microbe rich parts of your body; it supports more than 600 varieties of organisms including bacteria, fungi, and protozoa; viruses like herpes, gonorrhea and chlamydia are common, as are several species of amoeba. But mostly, there's bacteria, about 109 strains in every milliliter of your saliva on average, and it's supposed to be that way. Your mouth is the portal for all the outside stuff to enter your body and your saliva is equipped with anti bacterial enzymes to help keep that party under control. The eyeball has its protections too; there are epithelial layers which cover your cornea, the transparent dome in front of your eye. And it's lubricated with tears which also contain anti-bacterial enzymes called "lysozymes", but they are no match for the bacterial and viral frat party that's going on in your mouth. In fact, that is why you're never supposed to lick your contact lenses and though around 25% of contact lens users admit to having done so, I know none of you ever have. Because when the epithelial layers get infected, that's conjunctivitis with its itching and pain and redness and swelling and yellow-green discharge. But pink eye is really rather minor compared to what happens if you get an infection in your cornea, underneath that tissue. See, your tongue is covered with rough ridges and is likely to have lots of little scraps of food and junk on it, so it can easily tear through the epithelial layers on your eye and let all those microorganisms right into your cornea, which are your windows into the world. While pink eye will suck but run its course and be done, a corneal infection is a lot more likely to cause scars, eye ulcers, blindness, or in rare cases, even the loss of your eye. So yeah, if you have any sort of eye infection, go to your doctor. If it's just pink eye, you'll get some medicated drops, (you know that'll probably do for ya) but you don't wanna let a corneal infection run wild. Bottom line is: Kids, worming is not safe. Maybe someday someone will invent some sort of eyeball condom, but until then, just probably best to have other kinds of fun. Thanks for watching this episode of "Sci-Show News." We will not be answering many more sex questions but if you'd like to see more sex questions answered, you can check out "Sexplanations" at youtube.com/sexplanations. And if you have any questions, comments, or tips for new stories you'd like to see us cover, you can contact us on Facebook or Twitter or of course down in the comments section below; and as always, don't forget to go to youtube.com/scishow and subscribe.