We went to a wedding one, luckily parking wasn't very far, I just left my pump and supplies in the car, with a cooler and ice packs. I pumped in the car put it into bottles and stored them in the cooler, went back into the place and continued with my night.

Thanks for the tip Tara! I'm not too well versed in hand expressing but it sounds very convenient (storage bags and no washing!). Thanks so much ?

I’ve been finding that the easiest way for me to pump when out and about is to hand express. I don’t know if that’s possible for everyone I just have it down really well. I wash my hands and express straight into bottles and put a lid on them. If I am getting it back to my babies within a few hours I just leave them out. If they won’t eat them for longer than that, I bring a little cooler bag I have with an ice pack in it to keep the milk cold. If they aren’t eating soon you could also express straight into a storage bag, to save space in your cooler bag. I don’t like carrying around too much stuff! This process makes it so I don’t have to worry about washing parts/bottles when out and about!