The joke is that your family's low socioeconomic standing has forced your (likely single) mother to sell her body for pitifully low wages on the largely unregulated niche pornographic circuit. Despite the poor working conditions (including both emotional and physical abuse, as well as the ever-present risk of sexually transmitted diseases from all the rednecks she's banging) she has not missed even a single day, indicating a deep-seated self-loathing, probably stemming from birthing such an utter failure of a human being as yourself, Jessiah. The depths to which she has sunk are an attempt to externalize the shame of being responsible for your existence. Only when her public persona is as pitiful as you are will she experience any sort of emotional catharsis; hence her upcoming appearance in "Dong vs.: Jessiah's Mom." (It's a foreign film. Gotta love the Japanese.)