The doggy-style position allows for the deepest penetration for women. Often, it is deep penetration, as well as a lack of lubrication, that causes pain. You can use another kind of lubricant, such as Aqualube, in addition to natural vaginal lubrication to help minimize friction.
As for the depth of penetration, you can control it by putting your penis in a bit at a time, and then asking her to let you know what is pleasurable and what is painful. However, if during doggy-style sex your body is pounding like a pile-driver, Alice encourages you to reconsider the type, speed, and intensity of your movements.
One last thought: check with your wife to make sure doggy-style sex is something she really wants to do, or if she is interested, to find a more comfortable way to do it. Good sexual communication facilitates more enjoyable sex for you and your wife.
