I was about to say just hold it down but It sounds like you have a drop weight and that would be difficult. If you don't simply hold the racquet in place while applying tension with one hand. Once it finishes pulling hold with one hand and clamp with another, THEN release the tension and THEN let go.
I've heard a lot of people say how BAD this is for the racquet. I'm very doubtful of this since its no different than what is happening when applying a table break.
"I knit with fence wire for a living" .... its as exciting as it sounds.