A cover for receiving an implantable medical device includes self-anchoring protrusions that engage tissue of a pocket where the device is implanted to resist movement including rotation and flipping. The implantable medical device is placed into the cover prior to being placed into the pocket so that once in the pocket, the device may reduce rotating, flipping, or otherwise moving. The self-anchoring protrusions may include barbs of various shapes to frictionally engage the tissue of the pocket. The cover may include features such as a strap and elastic construction to assist in holding the implantable medical device within the cover. Apertures may be included to enable the device. The cover may include additional features like suture tabs to allow additional fixation via suturing the cover to the surrounding tissue.