It means that the parasite moved a comfortable couch, fridge full of beer and a gaggle of half naked women into its host's living room. And while the host surely will be confused by the lack of manners exhibited by the parasite, the parasite is a parasite after all, so in parasite world, all is right.
As an aside, I peeked into the window to see what the parasite did at night, and I found it reading this: