What environment are you hunting with your jerk cord?
I will give you some ideas that I learned last season with my jerk cord. If you are hunting from shore make a concrete weight with an eye bolt in it to place at your feet. Run the cord through that so you pull straight up on the line or however you want to pull it. Without this weight/anchor every time you pull you will rip your line across the surface of the water and the ducks will flair big time. You dont want them to see the line or ripples at all. If you are in a boat, run the line under the boat and pull it into the boat on the back side. This will keep the line underwater as well. Make your weight over 5lbs but doesnt need to be as big as ten. Anything under five or so will rise up when you pull creating ripples around your feet, which you dont want. You might know all this already, but I took your post as this will be your first time using one and hopefully these tips will help. Also, if you have some 60/40 keels use a few of them on the jerk cord as well. will short burst, they will dive head down and look like feeders.