In terms of speaking like a teenage in the urbanrap culture (brought on supposedly by the gang Blackstreet; See diggity) Piggity is the verbword of asking for a sample of something. This prase started in southern california used by mostly fans of underground rap.
Also a slang reference to a peice or pipe
"Can i have a piggity of your _____?"
"Dawg lemme get a piggity of that diggity dankness!"