Doc Johnson The FFISTERThe FFister is a thick and cushy sheath designed for DEEP dives. FFister is designed for comfort and ease of entry. The glove is fingerless, so your nails cant scratch. Knuckles are heavily cushioned, allowing for a smoother passage through the sphincter. This glove is quick and intuitive for the Top to put on. Just smooth it and burp out any air pockets. The FFister stretches well past the mid forearm, ideal for partners who want to go DEEP. No