The easiest thing I've found is a simple, small carabiner. They are solid aluminum, weight is minimal, and they can be found at almost every store. They don't need to be huge or "climber rated".
You can find them for a $1.00 or so, if you already don't own a few. And it gives you an optional place to hang some gear, just click your shoes or stuff sacks into the gate.
Any piece of pipe, tubing, a stick (about the thickness of your finger), a dowel, or arrow shaft will do.
Just make sure the whoopie is hanging on the strap, not the toggle itself.
I weigh 330 lbs., so they have pased the stress test.