One of Cetrion’s best moves to use up-close is her Natural Barrier. This is usually used after strings such as F23 to keep herself safe while creating distance.
Natural Barrier is -20 on block, but it can become -4 on block if Amplified, making her safe. Although the Amplified Natural Barrier is safe on block, the 2nd hit can be punished via Flawless Block.
If you would like to conserve your meter, you can also use a quick jab after Flawless Blocking instead of doing an U2. If Flawless Blocked, Natural Barrier becomes -14 instead of -4. Punishing this way can only be done if you Flawless Block very close to Cetrion. The best way to do this is to dash immediately after blocking the initial hit of Natural Barrier, then Flawless Block the 2nd hit.
This now creates a meta between Cetrion Amplifying the Natural Barrier and not Amplifying it. If you are looking for the Amplified Natural Barrier and try to Flawless Block, Cetrion can opt to not Amplify it. If you think that she will not Amplify the Natural Barrier, then use a move that is faster than 20 frames to punish her.
Some characters will also be able to punish Natural Barrier regardless of whether Cetrion Amplifies it or not. If your character has a 7 frame jab and does not get pushed back, you can interrupt the Amplified Natural Barrier. This is a guaranteed punish as it will cover both options.
It’s worth noting that this is dependent on the distance Natural Barrier is used. For example, if Cetrion does 11 into Natural Barrier, you will be pushed back too far to punish with a 7 frame attack. You will want to pay close attention to where Cetrion uses Natural Barrier so you know how to punish it.