When an author appears in their own work of fiction and interacts with the characters theyโve created.
The phrase is a nod to โBreaking the Fourth Wallโ, wherein characters acknowledge the fact that there is an audience/that they are in a work of fiction. (Famous example: Deadpool)
See also: metafiction
Dude 1: Do you ever read Pearls Before Swine?
Dude 2: Yes! I love how heโs always breaking the ceiling in that strip.
1๐ 1๐