From what I understand about Jing, the prenatal jing is like a savings account that you are born with. You can take from it, but you can never add to it. Once it is gone you die. Postnatal jing is more like a checking account. You can make withdrawals as well as deposits. Of course excess ejaculation depletes the mans jing, while having menses is what I understand to be the thing that depletes a womans jing the most. I also agree that it is best to conserve the prenatal jing while building up the postnatal jing. Activities that build up the jing include eating certain things like sea veggies, beans (esp. black and azuki), buckwheat, dried fruits, and foods with a salty taste. Of course, I would no advise using regular table salt, and of course don't overdo it with the miso. Too much salt can be contracting for the kidneys. Activities include taking small challenges, practicing courage in situations, and perhaps doing something a little 'naughty' that you could get caught doing. Just don't break the law or do anything where you could get hurt. Chi cultivating activities such as Nei Kung and meditation are probably the most beneficial activities one can do. And a ginger compress is a great home remedy which warms the kidneys and helps as well.