According to the description these can be used to exercise your vaginal muscles. I found that after inserting them the balls were so big that I needed to exert absolutely no effort at all in keeping them inside. Make no mistake, these are some big balls. I definitely would not use the for 'exercise' and they are definitely on the large size for a beginner, I myself am no beginner and I found them too large to be of any use for 'exercising' my vaginal muscles. Saying that these balls were very easy to insert, especially after adding just a bit of lube. Just be careful not to use silicone based lube as it will interact with the silicone in the toy and that would not be a good thing.

These balls do have a rather interesting 'self-vibrating' mechanism in them. You can definitely feel them 'vibrating' while inside you when you move around. You definitely need to exercise caution when removing the balls from inside you. They claim to have a 'sturdy' retrieval cord, however it is anything but sturdy. I certainly wouldn't trust it to not break when pulling on it for ball removal. I just pulled slightly on the cord and mostly used my muscles to push them out rather than pull.

I am not entirely sure what I would use these for. Other than for the feeling given by the slight 'vibrations' that can be felt while moving, even those feel a bit weird.

The balls themselves are made out of plastic and covered in silicone with heart shaped cut-outs. They are very smooth other than where the cut-outs are, but you can't feel the cut-outs at all during use. They are very easy to clean because they are made of silicone, just use a mild toy cleaner and let air dry - silicone toys pick up a lot of lint so I would not recommend drying with a towel, though I have found that paper towels work pretty well.

While the materials these balls are made of makes it easy to clean, the design unfortunately does not. Fluids can easily get under the silicone because these are plastic balls inserted into a silicone sleeve. In order to thoroughly clean it you have to remove the plastic balls through the heart shaped cut-outs, which is a very tight squeeze and then attempt to reinsert the same way after they are dry. This is a very tedious process, made even more tedious by the fact that the balls themselves are round, rather more egg shaped.

As for storage I just keep them in the package they came in. It is a small blister type pack that is only slightly larger than the balls themselves making it a nice storage size. This also keep it from contacting my other silicone toys. I found out the hard way that when silicone toys come into contact with each other they have a tendency to melt!