Ok so last night while we were fighting Lurker I went in my usual melee spot and when he spouted i jumped in and jumped out like usual.
Then, on the next whirlwind I didnt get knocked back at all.
The next time, still didnt get knocked back so I started looking around and found a spot where you wont get knocked back.
To do this you need to simply walk a little bit off the main platform, not to where you fall in the water, but to where your feet are in the water. This will stop the whirlwind from knocking you back so you can keep the dps up