{Stuffy Doll} is indestructible. If I tap it to defend a creature, is it destroyed? Example, a 3/1 attacks, I defend with Stuffy Doll, an opponent of my choosing takes the 3 damage. Does it kill Stuffy Doll though?
No because it is indestructable meaning combat damage unles it's infect can't kill it.
Nope. It is indestructible, means it will not be destroyed due to lethal damage.
Also you don't 'tap' creatures when they block.
Unless you mean tap on it in a way of pointing at it with your finger :)