A close friend who feels comfortable coming into your house via the side door, probably off the kitchen. You, too, are comfortable with this friend entering your house through the side door. A side-door friend is probably one of your best friends. Conversely, front-door friends are those acquaintances you are not all that close/comfortable with.
Marcia and me hang out constantly. She is totes a side-door friend.
The Urban Dictionary Mug
One side has the word, one side has the definition. Microwave and dishwasher safe. Lotsa space for your liquids.
Buy the mug