Imho, any time you take a Harley over 85 to 90 mph, you are taking a big risk. I've survived a few tank slappers - just barely, and it ain't no fun. I chalked that up to my crazier days, right up there with wheelies and burnouts, and I don't do that kind of stuff anymore. I trashed a lot of bikes, and earned a number of scars and knots on the noggin over the years learning the hard way. I do however have to agree that adding throttle briefly until things settle down can help if the wobble is getting worse upon decel. That worked one time, and another I just rode it out and it finally stopped as I got under 35-40MPH. A buddy of mine insists he slammed on the rear brake to do a blip skid and that helped too. I suppose at that point, try anything. Either you get lucky or you don't.
Thank God you're here to tell about it.