Terminology: POV stands for Point of View
The term "3rd person POV whiplash" is used to coin a type of writing that occurs when the writer gets carried away with POV changes, making the story look choppy and giving the reader "whiplash" as they are jerked from POV to POV within the story. Let's say, for example, that in your story, you are focusing on three main characters. Assuming you know the basic rules of writing POV (click here if you are unfamiliar with them), let's say that you have a paragraph dedicated to one POV, then you hop over to another POV for a full paragraph, and then switch to another and so on. As you read back the story, is it really necessary to have your reader climbing into that many heads that quickly?
In one case where this type of choppy POV change might be acceptable is during the climax of your story. The climax is supposed to elicit an adrenaline response from your reader and it can be amplified by fast changing POV's as the action takes place.
Otherwise, it's best to stick with one POV per page or so. If you have to show another POV of the same scene, do it after the initial POV instead of switching back and forth.