"Dine out on" is a phrase commonly used to describe someone who continues to talk or brag about a particular experience or event they've had. If you're looking for fresh synonyms, you might try "relish in," "linger on," "savor," or even "feast upon." These phrases convey the idea of someone thoroughly enjoying and taking pleasure in a past experience. Another option could be "chew on," which highlights the idea of someone mentally returning to a favorite topic or subject. No matter which synonym you choose, they all emphasize the idea of relishing and enjoying an experience, moment, or achievement.