Yeah, I know that was the look they were going for - and when a lot of people think of slip knot, they picture that, with a large loop you can put around something which you couldn't put it *over.*
I meant just tying a sliding knot towards the other end from the handle. It can be made tight and then used as a toggle-type slip-around loop or just used as is and the circle it makes being the perimeter of the enclosed object. Then it can be loosened, tightened, loosened, tightened.