Online 1/2, with straddle on to 4. Hero $450 effective Villain $700 effective. Only previous history is that villain is a little more splashy, and I stacked him with set over set a week ago. Hero UTG raises to $12 and folds around to the villain in the straddle who calls. Flop is Qs9h6s, villain checks, hero checks. Turn is the Qh, pairing the board and putting both front and backdoor flush draws available. Pot is $27, villain checks, hero bets $13, villain raises to $28, hero calls. River is Kd, pot $83. Villain bets $50, Hero raises to $140, villain tank folds.

Now, this is where it gets crazy. Hero has KK and villain has Q9 for full house over full house. I cbet with overpairs and AK on the more frequent side, so I decided to check the flop as part of my frequencies and for some partial deception. After that, in my eyes the hand plays out pretty standardly until villain makes an insane fold, which I see is even somewhat possible since I have zero line to representing any bluffs, and as soon as I raised he immediately commented on the hand we played a week ago where I sucked out on him for a turned set over set. My questions, is checking back this flop even 10-20% of the time a bad move, given that he called in the blind and could call with a variety of hands to a 3bb raise? I talked with villain after and said that if I bet the flop he's checkraising me which I'd obviously call, and then he bets large on the turn and I'd fold. I would never fold on the turn given that the board pairing reduces two pair and set combos and there's two draws to the flush out there, and then obviously I would stack him on the river. BUT, in the case where I didn't hit my two outer on the river, this check back would've actually saved me a lot of money (although this isn't really relevant as its results oriented.) What are your thoughts?