To give it all of your effort when you are tired and/or hungover. Using every last ounce of energy to power through and get the job done. Typically after multiple days of drinking.
“I am really on the struggle bus after the last few days of getting wasted, but I am going to chin the bar and party again tonight!”
“Did you see he passed out at like 9 last night?” “Yeah he couldn’t chin the bar!”
a very scary look that women of a certain age give their children when they have said something inappropriate, or have done something naughty. when her chin is fully extended outward and the face crinkles into a mean, scary expression, you have just gotten the chin