Cheese

(adjective) A person who strives to remain in someone's (potentially a superior's) good books and will do anything including feeding the persons ego or snitch on other people. Similar to a teacher's pet or prefect.

Derived from the relationship of a mouse and cheese. The person, or cheese, has no real substance or integrity, but a small minded mouse will always seek them (an eat them) to make themselves feel better. The cheese will also act all happy-go-lucky by smiling all the time (like saying "cheese" in a photo) and acting as if they are god's gift to the earth

Ex: You should never trust Bob. He is nothing but a cheese and will report anything said in confidence to our boss.