A story from about two months ago...
I am still trying to figure out atemi. Not doing atemi, but receiving them...
We were working on this technique were uke comes in with a yokomen-uchi, and nage does an atemi similar to a yokomen-uchi on the uke's opposite side. Uke goes backwards to not get thwacked, and takes a backwards breakfall.
Sensei had stopped us to give some instruction to my partne while I was uke. While he watched, I attacked my partner, had a weird feeling in my face, and then notied I was on the ground! I totally didn't react, took the atemi, and well.. it worked! I went straight down.
My partner: Oops, sorry!
Sensei: Thomas, are you ok?
Me (Getting up): Yes, I am good!
Then I tripped over myself trying to get up!
Then I got a brief, and apparently needed lesson on the importance of avoiding getting struck.
Later in class, Sensei surprised me with a yokomen strike, and I managed to not get thwacked this time