Using chain can be very horny. Some use galvanized chain, while others use the more expensive stainless steel chain. The latter being more resistant to rusting and a lot smoother. Make sure there are no sharp edges before playing. When inserting the chain into your hole make sure it is well lubed. The key is to hold the chain straight up and insert one link in at a time. Allow the chain to drop directly into the hole (as in the pictures below). It is important not to drag or drop the chain on the top and bottom of the hole as there is the potential to pinch the skin. The same goes for extracting the chain; Pull up and straight without letting the chain drop (again like in the pictures). For these reasons it is better to have a top feed you the chain, rather than try to play by yourself.