If you pump and BF you will produce more milk to keep up. If you want to keep some for later, freeze it or something, I'd just get yourself into a routine of pumping a little each day after a certain feeding, maybe after a light feeding, if you have one. I started pumping just a bit at first then more when my DD started on solid food so my milk stayed the same. Then when or if you go back to work, you can pump during the day and BF at night. It also might be a good idea to start pumping and giving him a bottle of it once in a while so he gets used to that too so you can be away from him when you need to later on. My DD took bothe very well that way. Good luck!
My daughter just started latching and she is going on 6 weeks. I pumped the first weeks and I would pump right before her feeding, but I would bottle feed it to her. Now I don't pump and only feed her on one side per feeding. I'm not producing too much milk anymore so I'll have to see how long that will last. I think if you pump on that one side the baby is not feeding off of then you should make more milk. Do I make sense?
With my first I was told to wait until 2 weeks before pumping, at 2 weeks what I did was pump the opposite side that my son fed from. I found that pumping right after feeding during day-time feedings worked the best. After I pumped a few times I even started to pump one side while my son fed from the other (the football hold worked best when pumping the opposite side). Either way it will increase your supply because you are expressing more milk, make sure that you have nursing pads on hand if you haven't used them yet as you might become full quicker. If you are just pumping to have some to use while you are out you might want to try only once or twice a day so you don't start making too much. Also remember that it takes your body anywhere from a few days to a week for you to notice an increase or decrease in supply, so you might not pump more than an oz here and there at first but after a week you should see an increase.
When I pumped to store milk for work I pumped once a day for about 3 or 4 days then I moved to twice a day. After about 8 or 9 days we started feeding one or two bottles at once to make sure he would take things for work. Just make sure when your son gets a bottle you don't give it to him, and don't give him more than one or two at once other wise you might start to notice issues with BF'ing. With my son after he had two bottles a day for a few days he completely rejected the boob. It took a month to get him to feed from me at night and I never got him to feed from me when he was awake.
Good luck! Also, use a little olive oil on your nipple when pumping. It will help it stay moist and won't burn when pumping and is safe for your son if he gets a little of it by accident.
Sorry if it's long and I'm giving too much advice. I really wanted to feed both my kids when I'm around but my son got lazy with bottles when we got him ready for me to go back to work and my little girl (Oct baby) is a biter and makes my nipples bleed if I feed her (She even bites the bottle a LOT when she drinks from it). I'm also faced with a fear to even try to feed my little girl at night which I so desperately want to do (so I don't have to pump at night!). Babies are lazy when given the bottle too often too early they are most likely to reject the boob (but not all babies).
I think the only reason why I want to pump is so that DH and I could go out and see a movie or I can run out to town and have a bit of time to myself every once in a while.
I don't plan on doing a bottle feed every day or anything...it was just going to be occasionally.