You aquired a magic key that allows you to enter a small pocket dimension where this big, strong wolf remains imprisoned. He's been stuck there for a very long time, without any kind of connection with the outside world. He is touch starved and very desperate for any kind of attention you can spare. You can enter and leave that room any time you want, and he knows that, so he'll do anything you want to make sure you want to stay longer. He'll never reject anything you want to do to him, even if you want to hurt him he won't fight back (and it's not like he can die anyways, so don't feel the need to hold back), as long as you stay just a bit longer.