As part of a two-year investigation, #Being13: Inside the Secret World of Teens, Anderson Cooper and his “AC360°” team connected with 200 eighth-graders at eight different schools around the United States.

They, along with their parents and schools, gave CNN and two child-development experts permission to review what they were posting on Instagram, Twitter and Facebook over a six-month period. So what better way to know what acronyms and other shorthand that teens, or in this case, 13-year-olds, use on social media than to scan their posts?

Here are some of the more popular acronyms and sayings, from the innocent to the racy.

1. OOTD — Outfit of the day

2. KOTD — Kicks of the day. Typically refers to sneakers

3. HMU — Hit me up. Usually asking for someone’s Snapchat username, a phone number to text or for a direct message

4. Smash — I would have sex with you. A girl might post a provocative picture and a boy might write “smash”

5. Cook session — When one or several teens gang up on another kid on social media

6. TBH — To be honest. A teen might post a picture of himself or herself and ask for a TBH, usually looking for positive responses.

7. TBR — To be rude. While TBH often leads to positive responses, TBR is usually followed by a negative response.

8. OOMF — One of my followers. A secretive way to talk about one of their followers without saying their name, such as “OOMF was so hot today”

9. BAE — Baby. Affectionate term for someone’s girlfriend, boyfriend, etc

10. WCW — Woman Crush Wednesday. A girl will post a picture of another girl she thinks is pretty, while guys will post pictures of girls they think are hot

11. MCM — Man Crush Monday. Similar to Woman Crush Wednesday, but featuring pictures of men

12. BMS — Broke my scale. A way to say they like the way someone looks

13. RDH — Rate date hate. As in “rate me, would you date me, do you hate me?” A typical response might be “rate 10 date yes hate no” or “10/y/n”

14. IDK — I don’t know

15. RN — Right now

16. KIK — Another social media app, Kik, that they want to communicate on

17. FML — F*** my life

18. AF — As f***. A teen might tweet “mad af” or “you seem chill af”

19. LMAO — Laughing my ass off

20. S/O or SO — Shout out

21. ILYSM — I like you so much or I love you so much

22. CWD — Comment when done. Similar to TBH, urging others to comment on their photo of whatever they are posting

23. LOL — Laugh out loud. Yes, you’ll still find teens using LOL and OMG.

• Courtesy of http://edition.cnn.com/2015/10/02/health/acronyms-teens-social-media-being13/