I might be the oddball here and say check the river. I don't see how a worse hand calls you. I can understand villian calling with Q8 on the turn, but I really don't think he calls a decent sized bet on the river with 2nd pair no kicker. Putting out a blocking bet will only scare off busted draws, hands that you want to bet into you, and I think it is very likely (ignoring results) that villian calls the turn with a straight or flush draw. Then again this is 25NL and anything's possible I guess. But yeah, like everyone else said, bet the flop. Rep that AK!