The sister get stabbed

The brother pick up the blade and stab his sister in the stomach with it.

"HEY. You're trying to kill me." The sister said, apparently she doesn't seem to react that much

"Does it hurt?"

"No. But it tickles"

The brother pull off the blade from his sister. No blood come out of it. He then look at the spot where she got stabbed. A hole has formed. Curious, he shove his hand in. The hole was kind of small through.

"Ouch" the sister suddenly yelped.

It seem that you need to use the blade everytime you want to stretch someone's skins. So you do just that. You widen the hole with the blade big enough to fit a object inside. Once you done, you shove your hand inside your sister.