This term is used to describe a feature in DAZ Studio whereby you hold down the Control key on your keyboard (Command key on Mac) when loading or applying a Preset to access options that control how that preset is loaded or applied. Pressing and holding the [Ctrl]/[Cmd] key down while loading a preset will cause a dialog containing any available options for that preset type to be displayed. Which options are available is dependent on the type of preset being loaded/applied.
[Insert screenshots and descriptions of the various option dialogs]
Accepting the option dialog will cause the preset to continue loading/applying, taking into consideration the options you have chosen.
All Control-Freak enabled preset types also each provide a common option to record/set an alternate method of loading or applying that type of preset, which is then bound to the Shift key. Once a preference has been set, holding the [Shift] key down while loading a preset will cause that preset to load/apply and take into consideration your alternate preference, but this will happen without displaying the option dialog.