Comfy
An informal shortening of comfortable. It often implies casual, friendly comfort: an adult wouldn't normally call a seat on the city bus "comfy", but he might describe his favorite chair that way.
Example:
Karin's guest bedroom was so comfy that her friends joked about being spoiled rotten whenever they stayed overnight.
Karin's guest bedroom was so comfy that her friends joked about being spoiled rotten whenever they stayed overnight.