it's when your balls are big and saggy. Anyway, you guys got the rhyme wrong both times.
Do your balls hang low do they wobble to and fro? Can you tie them in a knot, can you tie them in a bow? Can you throw them over your shoulder like a continental soldier? Do your balls...hang...low?
elephantitis is an unfortunate condition where the balls hang quite low. A lengthy colum of skin forms followed by two suspended balls. Often accompanied by shaven pubic hair.
ie. the balls can reach parallel to the patella, and in very extreme cases, the tarsals. "To patella and beyond!"