I am sure other dogs do it too, but the pack of social misfits that i share my house with, have raised this to perfection.
Whenever they have eaten grass or some unsavory thing found on their forays in the jungle, they choose the couch to throw up on.
If they want to munch on one of the greasy mini cocos that they find at this time, it has to happen on the couch
and if they get a bone, which is not often as I have learned my lesson, it will be devoured on the couch or one of the chairs.
All of it messy and all of it annoying.
The only good thing is that they still think of the floor as their private place to do their business when it is the slightest bit damp outside or,which is getting more common, they really, really don't feel like going out late at night.
I dread the day they get the idea that couches and chairs make fine toilets too.