Ain't no complaints

When there are no complaints to be had or something good happens this phrase can be shouted

"there's no homework"
"Ain't no complaints"

Pick up your pencil

When a perverted teacher looks at a girl's ass (or performs any other pervy actions) this is said (usually shouted) as a warning to the student or to mock or make fun of the teacher

"Oh no he's coming Pick up your pencil!"

"Lmao did you see Mr.Smith today he was totally looking at her she shouldn't have picked up her pencil"