To use the nipple suckers you apply the hollow end over the nipple, pinch the bulb to release the air from the bulb, and release to create a suction. If you just placed them as they are over the nipple, they would not suck, and instead would just fall off of the nipple. Depending on the amount of pressure you apply to the bulb, you can increase suction to the nipple/areola area.

The material of the nipple suckers is plastic, not rigid but not very soft. It's very durable, not stretchy, and not cheaply made. It should last a very long time. You can't do damage to this thing unless you really tried. It's very smooth on the inside and outside of the bulbs.

The shape mimics that of a nipple, but not really. The neck of the nipple sucker is what holds onto the skin around the nipple; the areola. The bulb is what creates the suction around the rim to keep hold of the body. It will fit anyone.

Depending on the pressure you apply to the bulb, you may be able to adjust the suction.

Unless you are lactating, you will probably not have to clean it as it goes on a body part that does not have liquid, and you probably won't get suction if you used body oil with the nipple suckers. They are easy to clean.

See experience section.

This was my first experience with the nipple suckers. They say mini, but they are actually pretty large. I didn't exactly enjoy this. I thought the suction was way too hard and it left deep marks in my breasts from the pressure. It kept a good suction unless you moved alot. During sex it would frequently fly off. If we tried to apply less pressure to the bulb to loosen the suction because of the pain, it would not stay on at all.