Try tapping on your pet, and as soon as it comes out, get the comb and comb it. That will reward it for coming out of the house. (Be careful not to tap on it when it comes out - that will "hit" your pet). As soon as you've finished combing your pet, try playing ball with it or give it one of its other toys. Be sure to comb your pet whenever he does something you like, and he'll soon be out of his house more often.