I find liners to be less squashing than lycra shorts, but they should still be fine. Might be a dumb thing to say but are you buying the right size? I find if they're slightly too small then the ballbag room is completely eliminated as they stretch. It's a fine line.

I like my zoic liner, tucks nicely around the gooch area but still has good room for the plums at the front. Means everything stays where it's supposed to and settling onto the seat is no problem. My endura liner by contrast is horrible, for it to sit in the right place I have to wedgie myself and the top of it is up around my belly button. Feels like I'm wearing a big thick nappy that's trying to wrestle itself into my bum crack. Wear it where it feels like I'm supposed to and the liner sags like those weird low swag sag pants that kanye wears.