I've had Howie 8 years and his sleep aggression (which is what you are describing) HAS improved to the point that we rarely have any "wake up snappy/growly" incidents anymore. I can't remember the last one. In the early days, however, I got him used to sleeping on a body pillow at the end of my bed and that is pretty much how we have done things (yes, totally dumb of me to LET him sleep on the bed in the first place but I don't claim perfection). Now, if we are cuddly on the couch, he is fine, but we did have the same exact thing you are describing happen early on.
One thing I did to try to desensitize him was to throw pillows or socks or stuffies at him while he was sleeping (every once in a while..not constantly!) to try to get him used to be woken suddenly. I think that helped.
We spent a good bit where he was not allowed on the couch when I was, too, but I eased up on that later on down the line. If you have kids or small pets, I don't recommend couch or bed priviledges.