Shake a thin layer of baking soda over the fabric of the couch, making sure to get behind the cushions. Allow the baking soda to sit overnight, and vacuum the baking soda away the following day. If you have pets, place garbage bags over the couch before you go to bed to keep them from tracking baking soda through your house.
Steam clean the entire surface of your couch. Equal parts of water and white vinegar can be placed in the reservoir, which will help to boost the odor eliminating power of the steamer.
Spray your favorite scented fabric refresher spray all over the couch and allow it to dry. This should mask any remaining odor and give the couch an approachable vibe.