Tail stalls occur from ice accumulation on the tail of the aircraft. The Cessna situation is a bit different and very rare.
The strange part about ICTS is that to recover you need to apply back pressure on the yoke and decrease power. No that is not a typo. Allow me to ellaborate.
In normal flight the tailplane or horizontal stabilizer doesn't lift up, it pushes down. It does this by acting like a normal wing but upside down. When ice accumulates on it and stalls the aircraft will pitch down because it has no force keeping the tail from rising. Back pressure on the yoke is needed to raise the nose back up.
Adding flaps will make the situation worse because of the change in airflow. The air flow that was once coming from in front of the horizontal stabilizer is now coming from above it. Remember not to think of this in terms of a normal wing stall, that is not what is happenning here. The horizontal stabilizer is acting like an upside down wing so when the airflow comes from above it this actually increases the angle of attack resulting in the stall becoming worse. Adding flaps also decreases the AOA of the aircraft and requires more force from the horizontal stabilizer.
Addition of power has the same effect, it increases downwash and the situation again becomes worse.
If this situation is encountered you want to remove any flap extensions, increase pitch, and decrease the power. I know it sounds crazy, but keep in mind all inputs will be opposite from a wing stall.
NASA did research on the subject and made a 15 minute long video that can be found at your local FSDO. If you want to understand this better I suggest you check it out. The video will illustrate this situation far better than I can on a computer.
Here is an AC with more explanation into the subject.