Sometimes known as “worming” – which somehow makes this whole thing worse – oculolinctus is being blamed for a significant rise in Japanese cases of conjunctivitis and eye-chlamydia, which is actually a thing. It’s apparently seen as a new second-base; the thing you graduate to when kissing gets boring.

The craze is thought to stem from a music video by Japanese emo band Born (there’s a chance that the eyeball-licking scene was only included to distract everyone from the fact that the song sounds like it belongs on a menu screen for an EA Sports game about snowboarding from a decade ago, but at this point that’s just speculation).

Tumblr, inevitably, is filling up with drawings and unnecessarily close-up photographs of the act, and YouTube is no stranger either. One theory about why it has taken off so spectacularly is down to the sheer number of nerve endings in the cornea. The eyeballs are incredibly sensitive because they need to detect grit and other small particles, and the sensation of oculolinctus is supposedly akin to that of toesucking.

Eyeball-licking: the fetish that is making Japanese teenagers sick | Life and style | The Guardian