Newbie question about blocking bets

[Riposte]

How can we ensure a villain makes a mistake by using a blocking bet on the river, if he is chasing a flush draw for example? Let's use this hand as an example... where we are putting the villain on a flush draw. This hand is entirely fictional...






Party Poker No-Limit Hold'em, $0.25 BB (6 max, 6 handed) converter

BB ($29.20)
UTG ($21.75)
MP ($15.48)
Hero ($27.35)
Button ($44.40)
SB ($21.15)

Preflop: Hero is CO with A[img]/images/graemlins/diamond.gif[/img], A[img]/images/graemlins/heart.gif[/img]. SB posts a blind of $0.10.
<font color="#666666">2 folds</font>, <font color="#CC3333">Hero raises to $1</font>, Button calls $1, blinds fold.

Flop: ($2.10) 8[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/spade.gif[/img], J[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $2</font>, Button calls $2.

Turn: ($6.10) 6[img]/images/graemlins/spade.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $5</font>, Button calls $5.

River: ($16.10) 2[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $8</font>, Button calls $8.

Final Pot: $32.10



On the turn, the villain called a $5 bet. Since his flush draw has 4:1 odds to complete on the river, he needs to win a $20 pot to justify his $5 turn call.

On the river, the pot is $16... what are we supposed to do? Check/fold? If we bet more than $3, the opponent makes a correct turn call... am I missing something here?