For many men, a penis ring is the "first sex doll " option. This in itself is simplicity: a ring that fits perfectly around the penis. Penis rings obstruct the flow of blood from the penis so that a man can remain more difficult. They are made of many different materials including rubber, metal, and leather. Some rings come with "bumps" on them, which many women find enjoyable during sex. Some rings also vibrate, which can be pleasurable for both men and women. In addition, some penis rings in India are made with a vibrating "extension" that can directly excite the woman.