“What do I do about people who donk bet pot after the flop hits?”

 
some counter strategies:

         click back flops with your air. nice price on the bluff. Villain strugle to 3b air with flops,
         even teh pros need to muster some courage for this line.

         stop opening hands that get pwnd by his weird 3b CIB range (middle suited connecters/gappers etc. that
         make middle/low pairs which cant stand heat)

         4b wide, small bet sizing. Make 1/4 cbets and barrell off scary cards. (CIB 4b for lulz and watch him think 
         “wtf” with a tank)

         be creative. think outside the box, be prepared to do weird shit (click backs, overbets, turn pairs into bluffs,
         abuse time bank)  

         Orthodox play gets abused, be the abuser.

make villains life hell. 3b him constantly. min raise the button and min cb flops. Try everything, throw the kitchen sink and really think outside the box. 

Watch Money Maker vs Eric Seidel in the HU tv series for the championship. Moneymaker throws every trick in the book. Fortunately for us we dont play Seiborg.