The place of First Escort can only be filled by a male of the Blood who agrees to a contract with a Queen. Once in this contract he is a primary member of the Queen's First Circle and is thus duty bound to her rule - though the breaking of the contract, while not common, is not unheard of.
The duties of the First Escort are literally to provide an escort for the Queen of his territory and to whom he has a contract with. He may also stand in the Queens place as something like an Ambassador when dealing with other Territories and acts somewhat as a business liason.
The First Escort is sometimes be intermingled with the Consort position, which holds the same responsibilities save one difference. The Consort is considered a lover, where as a male who is only named First Escort is not obligated to supliment those needs.