Teenagers have a secret set of Snapchat rules we never knew existed.

I have literally no idea how to use Snapchat.

Ever since downloading the app somewhere between one and three years ago (??), I’ve found myself fumbling around trying to work out exactly what I’m meant to be doing.

I’m not sending nudes. That’s not a thing.

I am filming my dog when he’s being silly, and getting snaps of cute babies in public, although of course I’m not doing that, because that would be highly unethical and impinge on people’s privacy.

What I do on Snapchat is so humiliatingly far removed from what celebrities and 'social influencers' (yes, I follow them for the lols) appear to be doing, that I've legitimately begun to feel like there's a secret set of rules I've just never come across.

For months, I've so badly wanted to understand how cool people use Snapchat, and I've come to the realisation that there's only one way to find out. I need to get a cool person to show me.

Enter: Caitlin*.

Caitlin is my 18-year-old cousin who also happens to be very, very cool. You know what I mean. Her Instagram is flawless. She has that impossible hair colour that only Cara Delevingne and approximately three other people are born with, and she instinctively knows the do's and don't's of any social scenario. SHE'S ALWAYS AT THE BEACH. She's just that sort of person.

So I asked Caitlin to 'pls explain' Snapchat. And you guys, there are rules. Rules that I definitely, 100 per cent, have not been following.

Ahem.

Don't send nudes.

Caitlin says Snapchat isn't about sending nudes. It didn't take long for people to realise that the whole "it only lasts a few seconds!" argument was inherently flawed, what with a little trick called a 'screen shot.' She says there's a million ways for someone to save a photo of you without you knowing, so no one wants to take that risk.

Well done, kids. Well done.

Have conversations.

Oh. Yeah I've never done this.

Caitlin says Snapchat is her most used app because it's easy to have really quick conversations without having to start a whole chat or message the person.

I remember this one time Kylie Jenner and Khloe Kardashian were having a conversation through Snapchat and it was really confusing - probably because they were sending them to millions of people who weren't each other. But now it makes sense. People use Snapchat to have conversations. Cool.

Snapchat streaks are a thing. A very, very important thing.

Ahh yes. A 'streak.'

That old chestnut.

So according to Caitlin, the fire emoji appears next to a friend's name when you've snapchatted them within 24 hours for more than one consecutive day. Then, the number next to the fire emoji represents how many days you've been on a 'snapstreak.'

You guys. Caitlin is on a 545 DAY STREAK WITH ONE OF HER FRIENDS. HOW.

She says she doesn't really care about streaks if they're under 30 days, but once the number gets higher, there's more at stake. 

You get emojis to show you're BFFs. This is important. 

My Story has a purpose. Use it.

Caitlin said one of the biggest mistakes people make is sending their friends the same snaps they've already posted on their story. No one needs to see the same snap twice.

If you're putting it on your story, you don't need to send it individually to your friends. It's a waste of everyone's time.

Don't get someone to take a photo of you.

Verrrry interesting.

According to Caitlin, if you get someone to take a photo of you, and then send it on Snapchat, it looks like you tried too hard. Snapchats should be selfies. They're low maintenance. Chill. Easy. It's not about posing and taking lots of photos before deciding which one to send.

Selfies. Only.

Just to clarify: You can take pictures of your friends and share those on your Snapchat. And your friends can take photos of you and share them on their Snapchat. But don't get confused.

HOW DID I NOT KNOW ANY OF THIS. AND WHAT MUST MY FRIENDS THINK OF ME. MY BOSS HAS ME ON SNAPCHAT. SHOULD I START A CONVERSATION.

Thank God for Caitlin's insight. Although, I'm still going to send snaps of my dog when he's doing something ridiculous. And of random babies on the street.

Oh. I mean, goodness me. Who could ever do such a thing? How rude.

Listen to This Glorious Mess: How to get your teens off their phones at night.