Mam bottles and pumping

Does anyone use Mam bottles? Do you connect them directly to your Medela pump? I'm trying to figure this out and haven't been successful. I can almost use a Medela to spectra bottle adapter, but it's not secure and I am afraid the bottles will fall while pumping. I would love to figure this out because I lose a fair amount of milk pouring from bottle to bottle. Any help would be greatly appreciated, thanks!