Whats with the oral sex poses?

[Betty]

So - I notice high school girls posing with their pointer and middle finger spread in a V below their chin with their tongue sticking out - for photos.

Back in the day - this had a very specific meaning. I'm wondering, has this gesture lost it's meaning, do these girls not know what it means, or do they know exactly what it means and are doing it anyway? Or was this a regional thing and no one knows about it but the high school I went to? (which I just can't imagine is the case.)