barfriend
A barfriend is someone whom you only associate with at a drinking establishment, ie. a bar. Often used in a romantic context, to mean someone whom you are flirty, sexually permissive, or even pretending to date when in the bar.
"My barfriend called me today, looks like I'm gonna be drunk again!" or "Listen, you're just my barfriend, not my boyfriend. What happens in Felix's, stays in Felix's."
barfriender
A bartender friend. The bartender you would go to for all of your drinks or go to for advice and conversation.
I'm going to the club to see my barfriender. He/She always takes care of my drinks.