One of the most iconic images of Oedipus in the 5th century BCE depicts the moment of his interview with the Sphinx. Here is a representative example (Beazley Archive 205372; Gregorian Etruscan Museum, Vatican City, Vat. 16541):
This is the moment when the Sphinx asks Oedipus her famous question. The iconic nature of this also makes it ripe for parody.
This is the best picture I could manage of the scene (if you are interested, see J. Boardman’s article in JHS 90 (1970) 194-195. This vase features the beast masturbating and ejaculating while the hero looks on and holds his sword. It is dated to the mid-fifth century BCE. (I found it in the LIMC, number 69).
There is a much more tame version of the later, which maintains the phallus, but skimps on the erections and ejaculations. This vase is in the Boston MFA, 01.8036.
This is incredible! What launched this line of inquiry?
I spent a morning looking over.dating for imaged of Oedipus for the Thebes project. This distracted me as wholly worthy of my attention