Its a combination of other tricks I used throughout the years:

1. Tilt your head backwards (a lot). Its recommended to lay down on a bed and then tilt the head back over the edge of the bed.

2. In this position, trickle a few drops of water into each nostril

3. If you did it correctly your nose/head will start to sting like crazy

4. When it starts to sting, instantly rotate your head into a forward tilt position and sneeze out the water. You will notice a very specific smell sensation while doing this.

5. Optional: After a couple seconds lay down sideways (must by sideways!) for a couple minutes and breath slowly. This step might increase the duration of the non-phantosmia period.

6. If the phantosmia seizure still is there: repeat these steps 2-3 times.

7. Tilt your head back up into its natural position / Stand up again.

I am no doctor, came up with this method myself and just started experimenting with it. So I don't know how good it will be long term, but so far it has been very effective.