Face-forearm
You're so ashamed you slap your face with your forearm like it's the last thing you can do before you die of embarrassment.
My brother told my mom he was going to be a pirate. Face-forearm. #piratefail
When I failed my math test and had to show it to my class. Face-forearm. #mathisdead
My friend told me his crush's name was 'Biscuit.' Face-forearm. #biscuitfail