You've most likely got a Shurz A Peep...

You've got a couple options. The first, which I wouldn't recommend actually, is to get a peep with the rubber tubing tied to your cable to ensure that the peep rotates around perfectly each time you draw. I feel that both this option and the Shurz A Peep arelast-ditch options designed for peope with inferior strings on their bows.

Hopefully, your bow came with quality-enough strings that you can throw away the Shurz A Peep and get a quality peep like a Fletcher Tru Peep. G5's Metapeep's have received mixed reviews, though of a similiar design because of many reports of them "flattening out."