squash (someone or something) (in) like sardines
To fit many people or things very tightly or snugly into a small space. We didn't want to take more than one car, so Jeff squashed us like sardines in his little sedan for the four-hour drive to Moab. Having a concert in our friends café was such a good idea! Sure, we had to squash people in like sardines, but everyone had a great time. I wish you would just let us buy you a bigger backpack! It makes my own back hurt watching you squash those books like sardines into your little shoulder bag.