How to crochet a woggle

Using thin (ish) string and a size 8 or 9 crochet hook, crochet a chain of 18, or however many you need with your string and hook to make a length 2½ inches long.

Join in a circle with a slip-stitch.

Crochet rounds of double crochet, being careful not to accidentally increase, until the woggle is the desired depth (mine took five rounds, but yours may require more or less depending on the thickness of the string and the size of hook used.)

Fasten off with a slip-stitch.

Cut off the remaining string, leaving an end about 4" long : thread this through a few times to fasten off then cut off the excess. Weave the starting end in in the same way.

The Woggle looks different on the inside and outside - see which you prefer and turn it inside out if necessary.