Spotted Dick is a boiled suet pudding. It's really a lovely dessert when homemade -- less tasty out of a can. Heinz Spotted Dick is a best-selling brand in England. Dick is an English nickname for pudding -- spotted dick means a pudding with currants or raisins (the spots). You can find spotted dick in Houston at the British Isles Import store in Rice Village and the British section of Fiesta supermarkets.
Puddink and puddick are nicknames for pudding that might explain the dick name. Or it could be a corruption of "dough." Some English hospitals have changed the name of the dessert to "Spotted Richard" on their menus due to the fact that dick is sometimes used as a slang word for penis. (No, really?) I suspect that most cans of the stuff purchased in the U.S. are used as gag gifts.