"Family Gay"
Season 7, Episode 8

In order to pay off some debts, Peter becomes the subject of a few medical examinations, including one that makes him become a gay man. In the eyes of creator Seth Macfarlane, this means that Peter becomes an avid shopper, and his steez meter increases accordingly. Slicked back hair, bold shirts, and striped pants are Peter's style statements of choice, and they definitely work for the big man.