Get your girl this Saint James sweater from Archival Clothing. Then explain to her that the pompom broach is an old tradition. French Sailors would put the pompom on their hats and the women would run by and rub the pompom for good luck. Girls love stories attached to presents.
Bonus tip: If I were you, I’d then ruin add to the sweet moment by telling her you have a pompom she can rub for good luck too…girls love when you ruin moments by making crass jokes about boner jams.