Tsume is a rather unique wolf in that his kind are able to create illusions on themselves so that they appear human to most people. Those who are good at sensing the supernatural or have high psychic perception abilities will be able to see through it either completely or for a brief second before it returns to the illusion. Animals will also be able to see through the disguise.
So what happens when someone physically touches Tsume or tries to attack him?
In the anime, it's kind of...weird. Usually when people shoot at the wolves, they are able to dodge them just from their high speed and agility. However, it has been shown that they can get upper arm wounds. While this would equate to Tsume's wolf form's forelegs, how it got shot there is somewhat confusing.
Technically, if one were to aim at their head, they would actually miss since the actual body is way lower. However, if one were to believe that the human form is more than just a projection of the image and an actual a sort of supernatural form that is still connected to its prospective wolf parts, then if some projectile were to hit the human form of Tsume's arm, then the wolf form's forleg would have the actual physical wound. But to the shooter, it will look like it hit the arm.
Whenever the wolves attack another person, they leave claw marks even though it may look like they used weapons, in Tsume's case his knife. Also, if it looks like they are reaching toward a person with the arm, it's actually their head and will use their teeth to pull on a person.
WITH CONSENT FROM THE OTHER MODS!
Tsume's human form will actually have more of a physical form. Meaning that when he's in his human form, the chances of him actually using an actual human body are higher. If he reaches out with his arm and it looks like he's touching with his hand, he actually is. I'll probably only do this if it would otherwise be brain breaking :|;
Usually I'll stick with the "he's actually using his wolf form to perform these actions" so I'll try to indicate it within the tags.
Hope that made some sense. ...It's still confusing for me, too xD