My dogs are house dogs, too, and once you let them on the furniture, it's very difficult to keep them off. I crate mine when I'm not around or there are people over who aren't "dog people" so the dogs aren't so much of a bother.
We now have a dog couch and they can go up there almost any time, but before that we conditioned them to not get up when there were people up there. If he's a softer dog inside, then you won't have to be too gruff with him, but he might just be trickying you to stay on the couch.
Here's what I would do:
1. Put him on a leash and make sure he's hungry
2. Have him jump up on the couch a few times and pair it with the word "up" or whatever word you want to invite him up on the couch.
3. Then get him off the couch, whether it's walking away, dragging him, shoving him... as soon as he's moving and on the ground say "off" or down or whatever.
Next time do the same thing but once he's gotten up and off a few times, sit down on the couch and don't let him up. If he gets up there, stand up, say off, and if he doesn't leap off, make him. All this with a leash on.
The other thing that I do is step on their leash so the only option is to lay down at my feet. If he knows the down command and is laying down, step on the leash about 6-12 inches from his neck. It won't be fun the first few times, but then he'll settle. It helps him learn that laying at your feet is a good place, too.