A whipped cream recipe that calls for the use of a "cold whisk" simply means that your whisk should be chilled, which you can do by putting it in the fridge for 15 to 30 minutes.
If you plan on whipping your cream by hand, wrap the handle of your whisk in a towel before chilling so that you don't end up freezing your hand off in the process.
If you're using a hand mixer or stand mixer, your attachments can be chilled just by moving them to the fridge. Use either a metal or glass bowl, as plastic isn't as effective.