Hi Ladies! Breastfeeding and pumping question?

Nadia

my son is two months old and I have exclusively breastfed him because I am a stay at home mom/ dairy farmer so it works with my schedule. however once in a while my mom or MIL will watch him for an hour or so. I want to have a bottle handy if he gets fussy or whatever. Can I pump twice a day? once in the morning after he nurses and once at night before we go to bed? I feel as that that will give me little by little enough to put in the freezer and defrost it when I need it? I don't want to have to pump all the time and I don't want to ruin my milk supply. HELP!