knuckle biter 

So hot you need to bite your knuckle to control yourself

Wow check her out, what a knuckle biter

knuckle biter by Jbw March 6, 2018

Polish knuckle biter 

When the outcome is obvious.
The opposite of suspenful.
Predictable.

Johnny is going to wrestle a bear. This is going to be a real polish knuckle biter.

Polish knuckle biter by Burt Macklin, FBI November 12, 2017