Assmaster

This is the aptly named Assmaster (south park reference). There is a fair amount of abuse on your backside, so I suppose it's a fitting name. You can hit the boof just about anywhere; the left is not as high, but go to far left and you'll be peeling yourself off the rocks along the bank. There are a couple other easy IV's after this before the mandatory portage (most use the left side) around Hanging Rock Falls.