It turns out the meme first surfaced in 2008 and was not just about "awkward smiles" but rather to label the expression on the face of a man before he is about to rape a woman. It's intended as a joke and you can find thousands of photos and videos on Instagram, Vine, YouTube and Twitter tagged #rapeface.
I hadn't hear of the term 'rapeface' before and I'm horrified by it. Horrified. The article does a good job of addressing how to speak to your kids about rape culture in a way that helps them understand the greater effect of their words on people.