O2BBubbleFree
Contributor
My whistle is one of those flat ones that has a belt clip on it (kind of like this one. I cut a length of cord about 8" long, and tied one end on the whistle (in place of the keyring in the picture) and the other end on my right shoulder d-ring. Then I tuck the whistle between the shoulder strap and the shoulder strap pad, knot end first. Shoulder strap pressure and the belt clip keep it in place. The cord is short enough that it's under the shoulder strap when stowed, and long enough that I can use the whistle without having to use my contortionist training to blow on it.