Pumping mamas¿

I'm thinking of pumping for my LO but how do you go about this in public? I strictly breastfeed my first and my books would get painful full within an hour of feeding him so confused how do you go out in public and pump or empty out your boobs to not be so uncomfortable. Of course we won't be out too often due to covid but we go out to grocery shop and things like that. I was thinking I could feed baby formula when I don't have saved up milk but I know my books are going to be throbbed and I also don't want to dry out my milk if I don't feed him as often as I should. I do have a haaka that ill be using too.