shove it sideways
A rather rude retort; the insinuation being that the intended audience of this request shove an object of questionable safety & hygiene sideways up their bum.
Teacher to pupil: "Chloe, i hear you flapping your busy little gums back there. Since you're currently receiving a "D" in this class, i'd think you - OF ALL PEOPLE!- would pay attention".
Chloe to teacher: "Shove it sideways, ya old bag!"
Teacher: "Whaaaaa!!?!"
Chloe to teacher: "Shove it sideways, ya old bag!"
Teacher: "Whaaaaa!!?!"