A mammy-jam is a traffic jam consisting almost entirely of, and caused by, women driving their children to and from school.
Boss: Why are you late for work?
Employee: Oh man, it's so frustrating. There's about three different schools on my route to work and I keep getting stuck in one mammy-jam after another.
Employee: Oh man, it's so frustrating. There's about three different schools on my route to work and I keep getting stuck in one mammy-jam after another.
by Alan "Mighty Morto" Morton January 2, 2009