I learned that these guys can swing on the willow tree in their side yard.
They wanted me to take videos of them, but we settled for a series of photos.
Its all very technical.
You must be sure you have a large enough handful of branches, you see.
Enough so they don't break under your weight.
But not so many that your hands slip off as you're swinging.
THAT would be swinging fail.
Looks like nephew #2 is a little scrawnier than #1.
(His handful of branches is pretty slim!)