There are some wonderful de-essing plugins available, but I have noticed over the years that often the best way of de-essing is to go in there and clip gain, or gain down, or volume automate down all of the esses. Frankly, all we really want to do when we are de-essing is turn it down! So this is a straightforward, old school technique that does that super quickly, without the need for fancy plugins!
To start, we are going to duplicate the vocal, and then remove all of the plugins from the duplicated track. On the track I demonstrated this trick on, the most abrasive esses were at about 5.5K. So I took an EQ, when in at about 5.5K, made the EQ really tight, and then gained it up.
Then, I can also high pass it all the way up to that point, so there is nothing below 5.5K, and then do the opposite and low pass it right up to that point as well. What we are doing there is highlighting that area. Next, I took the duplicated vocal and sent it to a dead output. Then take a compressor (any compressor you have will work!) and apply it to that point, and then I turned the attack and release to the fastest time. This will simply turn down the point where the esses are at the loudest.
Watch the video below to see this de-essing trick in action!