How can I keep my couch slipcovers in place?

My couches have a lot of life left in them but the leather-like surface is peeling and looks ugly. I found some slipcovers I really like, I am just trying to figure out a way to keep them from roaming around as we sit on them. They are all tucked according to instructions. Tried the rolled up newspapers or pipe in the cracks, but it comes down off the top too. They just need more ..... convincing, to stay put. Thanks for your help.
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