San Fransisco Muffin Share definition Flag The vagina of a man who had a sex change to a woman who lives in San Fransisco. "Dude did you see Karly's San Fransisco Muffin last night? that snatch didnt even look like a pussy" San Fransisco Muffin by PheeNoIVI September 28, 2009 0 0 Get merch Get the San Fransisco Muffin mug. Buy Now — $32.95 See more merch