I hate being checkraised

[AE6]

Villain has been playing 31/21/2.4, but honestly hasn't really been getting out of line too much. He hasn't been caught showing down much trash anyway, it seemed to me at the time like he was semidonkish and just running good.

I have like ~100 hands with him all from this session and I have been catching a few cards so if he's been paying attention, my image is probably pretty LAG. I think i was something like 26/22. I mix quite a few flop checks into my game and only cbet like 55% of the time, doubt he knows this though.

PokerStars No-Limit Hold'em, $1.00 BB (6 handed)


SB ($89)
BB ($102.55)
UTG ($99)
Hero ($205.30)
CO ($203.45)
Button ($122.90)

Preflop: Hero is MP with A[img]/images/graemlins/heart.gif[/img], Q[img]/images/graemlins/heart.gif[/img].
<font color="#666666">1 fold</font>, <font color="#CC3333">Hero raises to $4</font>, <font color="#666666">2 folds</font>, SB calls $3.50, <font color="#666666">1 fold</font>.

Flop: ($9) K[img]/images/graemlins/diamond.gif[/img], Q[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, Hero checks.

Turn: ($9) K[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
SB checks, <font color="#CC3333">Hero bets $7</font>, <font color="#CC3333">SB raises to $20</font>, Hero. . .

If I call here, how much should I be willing to put in on a 2c river?