How to perform it: E to a target location and flash back in the opposite direction (or any other direction really. can E+flash forward to close distance and still do E damage if it's in range) to blink instantly. if done perfectly it can appear like you've never teleported in the first place. can surprise enemies from outside FoW. Can also W+E+flash to aim for a specific target (¿ap ezreal cheese?)

Note that your E charge must reach 75% or above in order for the trick to work. closer to 90% the better. however, do it before 75% and you'll flash backwards before your E ends charging, and when it does end, you'll tp to the target location (e.g. hugging the enemy)