Much like the definition of “stick up your ass,” this is used to describe a strict person - however, this version describes it to a rather extreme extent.
You people never let me do anything I want! Forget the stick... you’ve got the whole tree up your ass!
phrase used by Levi Ackerman because he was done with Eren Jaeger's bull shit screamfest in the woods so he took it upon drastic measures to give him a life lesson on nature
" Hey Eren, take a look at these big asstrees" -Levi