Internet meme that came about after some kid said it on a comment when Youtube.com was raided with porn. Usually said after something that adults talk about/kids wouldn't get. Not to be said in real life, like most other memes.
Anon A: I was wondering, do you guys prefer anal sex or vaginal sex?
Anon B: I'm 12 years old and what is this?
Anon A: Do you think its worth it to have sex without a condom?
Anon B: I'm 12, what is this??
Anon A: My girlfriend just blew me, shit was SO cash.
Anon B: inb4 I'm 12 and what is this
Anon C: I'm only twelve, what is this?!