When a guy is getting head.
Friend 1: "How was that date last night?"
Friend 2: "Totally ended up stabbing face!"
Friend 1: "Nice." (accompanied by high five)
Being excessivly hard on yourself for mistakes made and/or opportunities missed.
Openly admitting being wrong at the expsense of dignity or self image.
After letting her walk out of his life for the last time, Max was stabbing face for months.