To be banished from one's room (most often, a single-space dormitory room) so that the roommate may engage in private sexual intercourse. Generally speaking, sodomy, cunninglingus, fellatio, and most forms of foreplay consitute grounds for sexiling.
It is a common phenomenon at college, often done willingly by arrangement, which may include telltale signs to show the room is being used (i.e. a strategically placed sock or tie). Where sexiling becomes too regular and inconsiderate, the solution is another Urban Dictionary favourite = Cockblocking.