They accidentally call you “baby” (not in bed).
Your friends not only know his name, but they ask about him too.
You text him “What R U Doing?” and you actually just mean “What are you doing?”
They text you before 8pm.
They spend the night, you both sleep in and get brunch the next day.
They ask how your presentation/test/interview/trial went.
You know anything at all about what happened in their life between hookups.
They call you. On the phone.
You post a link to their Facebook wall.
They loaned you a book. (You don’t loan a booty call a book.)
You allow yourself to be photographed with them.
The two of you are hanging out. Sober. Not hungover.
They invite you out to the bar with their friends before they’re ready to leave.
They know your middle name.
You kiss as a greeting (not just as a pathway to sex or out of obligation in the morning).
You’ve, of course, never met their parents… but you do know what they do for a living.
They text you “Thinking of you,” and there’s not a dirty picture attached.
You “have a relationship” with their pets(s).
They post something to your Facebook wall and you don’t fly into a panic and delete it immediately before anyone sees.
You don’t have a drawer or anything, but you’ve left some article of clothing at their house and you kind of like that it’s there.