Fling Sock Field Manual

They call it a "Fling Sock." We called it a "Schmerltz." They make theirs as follows:

Bean bag end - Sinks securely into the palm of your hand. Double bagged and filled with non toxic polyethylene pellets(the same material used for sandwich bags)
Tail section - Made of durable tie dye colored nylon fabric. Trails behind the bean bag when thrown providing a long, easy-to-grab target.
Handle - Soft foam enclosed in heavy duty nylon. Provides a specific comfortable place to hold so the spin and timing for release are always the same. That means your throws will be consistent. Keeps the tail from sliding out between fingers so tail catches are automatic.

We made ours by putting a tennis ball into the toe of a sock and making a knot above it (or not).

Whether you make your own or buy the commercial version, here's a Field Manual for many hours of active and attractive flinging.

From the perspective of someone facilitating a play event, these Schmerltz/Fling Sock thingies, once in flight, are as eye-pleasing and crowd-gathering as a Frisbee. The tail flutters in the air like a giant sperm. Throw a bunch of them at once to fertilize the playful imagination.

From the players' perspective, the Field Manual demonstrates how many different ways there are to play with this toy, and how inviting it can be for people of all skills and ages.