June 9th is the day of each year that every man (or person with both a dick and an ass), who also posesses a female significant other, sends her a picture of their dick and ass. It can be separate, or together, but both the dick and ass must be photographed and sent on this day, if mentioned.
GF; "Hey babe, do you know what day it is?"
BF; "Yea, it's June 9th. What's so special about it?"
GF; "Today is June 9th, "Send your Girlfriend pictures of your Dick and Ass Day""
BF; "Well, shit, let me get to taking pictures then!"
Your girlfriends' best friend who's basically the third person in your relationship and not in a weird cockblocking sort of way she just fits among you and girlfriend and you couldn't imagine your relationship without her in it because she's not just girlfriends' friend... She's yours too. She drinks with you when girlfriend doesn't want to. She goes and eats with girlfriend when you're on a diet. She takes girlfriend to target when you don't want to go. She is an associative girlfriend and your favorite third wheel.
Example 1
Girlfriend:I'm hungrylets go eat allll the foods
You: no go call associative girlfriend I'm on a diet