Brewer's: Sleeve

To hang on one's sleeve. To listen devoutly to what one says; to surrender your freedom of thought and action to the judgment of another. The allusion is to children hanging on their mother's sleeve.

To have in one's sleeve

is to offer a person's name for a vacant situation. Dean Swift, when he waited on Harley, had always some name in his sleeve. The phrase arose from the custom of placing pockets in sleeves. These sleeve-pockets were chiefly used for memoranda, and other small articles.

To laugh in one's sleeve.

To ridicule a person not openly but in secret; to conceal a laugh by hiding your face in the large sleeves at one time worn by men. Rire sous cape.

To pin to one's sleeve,

as, “I shan't pin my faith to your sleeve,” meaning, “I shall not slavishly believe or follow you.” The allusion is to the practice of knights, in days of chivalry, pinning to their sleeve some token given them by their ladylove. This token was a pledge that he would do or die.

Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894

Sleeve of Care

Sleepy Hollow