Slip for couch cushion?

[sparksfly]

My parents bought a couch about a year ago made of fake leather. One of the cushions is falling apart. The fabric on top where you sit is all ripped.

My father went out and bought some fake leather that matches the couch perfectly[it's basically the same fabric] and since I know how to sew he wants me to to make a slip cover.

The only problem is the couch cousins are sewn into the bottom of the couch. There not completely sewn if that makes sense so you could make something and slip it under, not completely.

How would I go about making a slip cover for it?

I was thinking of something like this: but bigger. Just so I could slip the edges under the cushion and so it would stay in place.

[kaz814]

I think that could totally work.  Or you could add snaps or velcro or something, so you'd be sure it wouldn't slide off.