Another Semibluff 3-bet turned bad

[GTSamIAm]

CO open-raises, he's marked as 29/25/2 with attempt to steal 44% over 100 hands. Folds to me in the BB with Q [img]/images/graemlins/club.gif[/img]9 [img]/images/graemlins/club.gif[/img]. I reraise and he flat calls. Board is:

K [img]/images/graemlins/diamond.gif[/img]6 [img]/images/graemlins/heart.gif[/img]6 [img]/images/graemlins/spade.gif[/img]

Really dry flop and I'm oop. Wonder if check-folding is the best play here or just a normal continuation bet is best over the long term.