I just recently started pumping so my DH can help feed and will be easier to leave the house. I have a few questions for those who pump. How do you give it? Do you heat or just give cold? How about if you want to leave the house. Can you just take it and let it warm up on its own, keep in diaper bag or should you warm up before you leave? If they don't finish a bottle can you put in fridge and use next feeding if it is just a few hours or so you just throw away? I'm a FTM so this is all new to me.