A phenomenon resulting from anal sex where ejaculate builds up inside the rectum and is shortly followed by a sizable bowel movement. A proper white zeppelin occurs when deposited semen completely coats the outgoing feces, resulting in a smooth and hearty plop within the bowl.
Doctor: I'm glad you are no longer having problems passing those massive turds. Did you heed my advice and become a vegetarian?
Patient: No, I've found that a good WHITE ZEPPELIN works wonders after an all-u-can-eat-meat buffet.