Petulia is the Goddess of Negiotiable Affection and therefore the patron of all seamstresses. There are very lifelike statues of her in Ephebe which are worth a visit. She has not appeared on a Discworld stamp  yet, but The Guild of Seamstresses in Ankh-Morpork issued a cover to mark her feast day in the Year of the Happy Goose. For Discworld Stamp Collectors, this is an essential addition for their collections because the One Penny Virgin stamp only appeared on this cover - apart from a few sheets awarded to prizewinners in the Stanley Howler Stamp Journal.
The stamps were printed in sheets of 24 with the bottom four stamps being a wonky p sport. Hence one in six covers will have a sport stamp affixed.

The common (left) and the Sport (right)