Back hand smile
A Back handed smile is when somebody smiles without actually showing their teeth or fully grinning. People typically use it when they're too ashamed or self conscious to smile. It is typically used by actor Wyatt Oleff during photos with fans or just in general. It looks incredibly forced and awkward. Its practically smiling yet frowning at the same time.
"Hey dude! Don't back hand smile and just smile normally!"
"But I don't want too!
"But I don't want too!