You can buy vaginal ball with or with out retrieval strings. A beginner might want to start with a string type; they're easier to retrieve (not that they can go anywhere, because they can't) and chances are, because they are joined, they won't both fall out! Whereas, if you have just the balls in, and your muscles aren't in great shape, they could fall out. I usually find just one will pop out if I cough hard or sneeze! Obviously I need a little more work with them1 As well as strengthening muscles (and your partner will notice!), they provide a discrete source of constant stimulation.