A disposable absorbent insert for fitting against a forehead-contacting, curved inside surface of a user's athletic head covering includes a moisture wicking layer; a liquid absorbent core layer; a liquid impervious layer; an adhesive layer comprising a repositionable pressure-sensitive adhesive; and a release liner layer. A top edge of the insert includes a plurality of slits to facilitate fitting of the insert onto the curved inside surface of the athletic head covering. A method of using a disposable absorbent insert on a forehead-contacting, curved inside surface of a user's athletic head covering is also described.