How to unlock: After entering the Vault 81 (Vault 81 quest) (M6,3)
Inside the Vault 81 you can find a classroom. It's in the northern corner of the location, on the floor. Talk with Katy the teacher, she will give you a short quest. You must tell a story to the kids. You will be deciding what to tell by selecting various dialogue options.
Quest rewards: Some experience and Grognak the Barbarian magazine.