Let's face it: You're practically in a polygamous relationship with each of your best friends. And that's OK. Excellent, really. Nothing like that "Sister Wives" show. More like every sleepover montage you've ever seen plus two-buck Chuck plus French fries.

So how do you know if you're in a real relationship with your BFF(s)?

1. You know all the details of each other's love lives.

ALL the details, not just the SparkNotes version.

2. "Crapchats" have become a normal form of communication.

You two share about every other aspect of your lives; your bowel movements are no exception.

3. Sometimes you don't even need to speak out loud for them to understand you.

Some things go without saying, like, "I need a refill" or "I need a girls night," for example.

4. You know exactly how to entice them.

"We're ordering Chinese food," and I'm there.

5. Being productive together doesn't always work out.

"OK, we should do our homework."

(Two hours later...)

"I can't believe I didn't get any work done."

6. Pants are 100 percent optional.

In fact, it's abnormal to wear "real" pants around them. Yoga pants and sweatpants only.

7. You might not get out often, but when you do, it looks something like this.

Followed by frozen mozzarella sticks at home, obviously.

8. You don't Instagram any group pictures without their permission.

And you might even be willing to sacrifice the one you look best in for what is best for the whole group.

9. You've definitely been mistaken for a couple. On more than one occasion.

But if it gets you a family discount, own it.

10. You always know what's best for each other.

Always ice cream. Always.

11. You always know the right thing to say.

Sometimes it just doesn't come out right.

12. You've been through thick and thin with them...

13. ...but you always know how to make the best of every situation.

14. And even though you don't always agree on everything...

15. ...you guys can always find common ground.