How can I enable double-tap and drag on the new MacBook Pro?

I just upgraded to the brand new MacBook Pro from a 2011 model. On the old machine I could drag an icon by double-clicking on it and then dragging it (the drag function worked even if I took my finger off the trackpad for a second, which I found extremely useful). I've visited the Trackpad options under System Preferences many times on the new computer and tried to find how to set this up but I can't seem to duplicate this function. As it stands, I force click and have to keep constant pressure whilst dragging which is sometimes difficult to do when trying to drag something from one end of the screen to the other. I'd be very grateful if someone could advise.