M2M Nipple Suckers Silicone with Ring Black. Nipple suckers can be applied to either male or female nipples. The suction provided makes the nipples erect and increase the sensitivity to the nipple. Prolonged and/or frequent use of nipple suckers helps to add length to the actual nipple. Nipple suckers from PHS International are made with high quality silicone and are available in black or clear. Silicone is 100% skin-safe and contains no phthalates.