Nipple Suction Cups
These Nipple Suction Cups are small but nice. Easy too: Lick them, squeeze them, put them on your nipples and they will suck them in. Since the wand of these suckers is relatively thick, the suction these little cups provide is actually quite good.
Internal diameter 10 mm so relatively small. Intended mainly to enlarge / sensitize the tip of the nipple only. A larger diameter would lessen the suction. Suction cups for larger or pierced nipples are also available @ Mister B, check out the 663110 Butch Nipple Suckers.
Sold as a pair.