The best i can do is give examples of what i mean.
In "Rosario + vampire" the main character has to keep hidden the fact that he is a human in an all monster school lest he be killed.
In "oran host club" the main character is a girl who has to pretend to be a boy and work off her debt.
In "Mayo Chiki!" the main character has to pretend to be a boy or she will lose her job as a butler.
I like these types anime because they often get themselves in extremely awkward situations