After the Fairy Council takes Cosmo and Wanda away from Timmy (For his secret wish) and Father Time set time forward 50 years. Without a godchild, Cosmo and Wanda briefly return to live in Fairy World. Cosmo, Wanda, and Poof are returned to Timmy of course at the end of the special, so they effectively no longer live here.
Cosmo and Wanda's House looks similar to most other homes in Fairy World. The entirety of the exterior of the home is different shades of pink aside from a wand-like structure on the roof (Possibly an antenna or satellite). The most notable difference is that the house is oddly placed inside a massive fishbowl, reminiscent of when they live with Timmy. The location of the house is on the corner of "Cosmo" and "Wanda".
Not much is seen of the interior as it is only briefly seen during the episode. Only the entryway is seen. Like the outside, the interior is almost entirely various shades of pink aside from a yellow bench along the wall.