FREE TUTORIAL | make a Wet Felted Cat / Kitten Cave | "To assist a Felt Maker to create 3D Pod or Vessel using a resist shape. The resist can be made from thin plastic, bubble-wrap, or even a piece of cardboard.(Options include using a water balloon to support the interior during felting in a dryer.) A resist is needed to prevent the two sides of this project from fusing together, so a 3D vessel is created." Not a very-first felt project, but with these instructions it's achievable.