The vallain has 22/12/??/41hands. he is pretty donkish and bets cbet 100%. once, i have cr'ed him on a J 10 4 flop and check folded on the turn once.

Full Tilt Poker $2/$4 No Limit Hold'em - 5 players
2+2 Hand Converter Powered By DeucesCracked

BTN: $898.00
SB: $479.00
Hero (BB): $436.00
UTG: $400.00
CO: $512.40

Pre Flop: Hero is BB with A J
1 fold, CO raises to $14, 2 folds, Hero calls $10

Flop: ($30.00) A 7 T (2 players)
Hero checks, CO bets $24, Hero calls $24

Turn: ($78.00) A (2 players)
Hero checks, CO bets $60, Hero calls $60

River: ($198.00) 6 (2 players)
Hero checks, CO bets $204, Hero folds

wtf... why are you folding?
I would 3-bet PF here quite often.
As played I would c/r the turn and hope that he puts me on a bluff or some kind of draw. As played I bet river myself and call his shove. Your hand is underreped

damn im terrible. i just assumed that this donk wasnt capable of 3 barreling. I thought he had a FH or a higher Ace

also i didnt 3 bet b/c i was pretty sure he would flat it pf. is it always a 3bet against donks or is calling better?

Im ok with your line as long as you call the river

call river and its okay

whats wrong with him calling PF?

This would be the bottum of my range for calling AJs pf. I would be in this situation with AJs which I can call or 3b pf (both fine), which is basically ending up the same situation. I would def 3b pre or fold AJo tho.

c/r the turn is awful advice imo. wtf is he calling us with that we beat, and wtf is he folding that beats us.

river is more interesting. c/f is ok imo since bluffing this river is totally insane.

His pfr is 12%, so from co it is prob about 20% and against that, we can raise AJo. It's not far from borderline though, so folding is ok too. If we call though, we need to make up some EV when we miss too. If you aren't prepared to do this, then fold/3b > call