When I was a kid, my grandpa would chase me around his house with a pussy willow branch.
That is what I thought Dyngus Day was, a grown man running around silly with a branch.
This morning I read that it is also known as "Wet Monday". Kind of disturbing, thankfully, they didn't choose to call it "Moist Monday".
Dyngus Day is the secular celebration after Easter, egg rolling, dancing, and soaking people with water. The pussy willow was tapped on girls by boys, showing affection toward them. That is now working both ways, girls tapping boys. But more interesting is the evolution of the "wet" part of this day. It used to be sprinkles. Not anymore, check out this video:
For more history on Buffalo Dyngus Day, check this out.