Wax play is a type of play in BDSM where hot, liquid wax is dripped from a candle onto the bottom's naked body. This results in a burn-like sensation, which however normally leaves no permanent marks on the skin and does not require treatment, other than removing the cooled-down wax from the skin later and taking a shower.
Alternatively to dripping from a candle, hot wax can also be ladled onto the bottom's skin. Wax play is possible on practically any body part, including (if the bottom is able to take it) near or on the genitals. Ideally the skin should be hairless or shaved smooth, otherwise the wax will be difficult to remove later.
The temperature of the wax depends on various factors such as the type of wax, the type and size of the candle, and the dripping height. The higher, the more the wax will cool down before it reaches the skin.
The top can be creative as to where to drip the wax, anything from sprinkled dots to bold lines of wax is possible. With enough candles, it is possible to gradually cover large areas of the bottom's body with wax. When candles of differerent color are used, the result may become an artwork with its own aesthetic appeal (see example photo).
Wax play is messy and is best played with a PVC sheet underneath that can be easily cleaned. Because of the mess it makes on furniture and the floor, wax play is forbidden in some public BDSM locations; in others it is permitted, but only in designated areas.
Wax which is too hot can cause serious burns; such as beeswax candles. A good type of candle to start with is a plain paraffin candle. Paraffin candles can easily be found among candles sold for religious purposes. Wax heated in any sort of pot must be stirred vigorously or there can be dangerous temperature variations. Wax can also splatter into the eyes. More safety notes on wax play can be found on Wipipedia (see link below).