A bar mitzvah is a jewish celebration of a boy reaching age 13.
This age is usually the beginning of puberty, and followed by a new addition on the upper lip.A magnificent, yet awkward weird soft fluff moustache.
which is the bar mitzvah moustache.
One can be defined with having a bar mitzvah moustache regardless of his age, religion and sexuality.
"Hey bob! Great bar mitzvah moustache! it's softer than my baby sister's hair!"
"that girl thinks no one sees, but she clearly got a weird bar mitzvah moustache going on"
"I'm sorry guys, can't join movember, my bar mitzvah moustache doesnt want to normalize regardless of the amount of times i shaved it"