Villain should rarely be opening 44-66 from UTG and even if he does it's a much smaller part of his range than ours, he shouldn't really have 78s either. Flatting his 2x open from the CO we definitely have all the sets, two pairs, as well as the nut straight here and they should be a much larger potion of our range as well so I think we should be able to play this board hyper aggressively. I could've maybe just tried to check down 33 but I thought the 2 extra outs it gives me made it more valuable as a bluffing hand. I think we also don't really many other clear bluffs here apart from A3s,A7s to balance out our made value hands.

Any reason not to spew off all of our chips here?

888Poker Snap, Hold'em No Limit - $0.05/$0.10 - 6 players

Replay this hand on Upswing Poker - https://upswingpoker.com/replayer/1a1N6bEE
xarichi (UTG): $13.13 (131 bb)
Kocky.10 (MP): $11.91 (119 bb)
JackOscar95 (CO): $10.32 (103 bb)
satoshi01 (BU): $24.55 (246 bb)
Jenich87 (SB): $10.23 (102 bb)
x5blufff (BB): $12.35 (124 bb)
Pre-Flop: ($0.15) Hero (JackOscar95) is CO with 3♠ 3♥
xarichi (UTG) raises to $0.20, 1 fold, JackOscar95 (CO) calls $0.20, 3 players fold
Flop: ($0.55) 6♦ 5♠ 4♣ (2 players)
xarichi (UTG) bets $0.36, JackOscar95 (CO) raises to $1.18, xarichi (UTG) calls $0.82
Turn: ($2.91) Q♣ (2 players)
xarichi (UTG) checks, JackOscar95 (CO) bets $2.26, xarichi (UTG) calls $2.26
River: ($7.43) 9♦ (2 players)
xarichi (UTG) checks, JackOscar95 (CO) bets $6.68 (all-in), xarichi (UTG) calls $6.68
Total pot: $20.79 (Rake: $1.03)
Showdown:
JackOscar95 (CO) shows 3♠ 3♥ (a pair of Threes)
(Equity - Pre-Flop: 19%, Flop: 22%, Turn: 14%, River: 0%)
xarichi (UTG) shows 7♣ 7♥ (a pair of Sevens)
(Equity - Pre-Flop: 81%, Flop: 78%, Turn: 86%, River: 100%)
xarichi (UTG) wins $19.76

I think there's plenty of reason not to spew all your chips there.

At this limit, villain isn't folding any overpair on that flop, and clearly doesn't seem to be too bothered about the turn.

I also don't think you can rule out all sets. A lot of players (including me) will open all pairs UTG. Flopping sets is too EV+ not to.

Maybe its true, that you have some nut advantage on this board, but what does it matter, if Villain will call you all the way down with 77? You just picked the wrong opponent here, and this is one of the issues with fast fold games, because its just difficult to get a solid read on anyone. Also your hand had some showdown value, so there is much less value in turning this hand into a bluff than for instance a hand like 97s, which has no showdown value. Call flop, call turn if he bet a reasonable size, fold river.

One other thing is to bear in mind that some players, if they flop an overpair, they will rarely if ever fold, no matter what comes on the turn and river.

I am not an expert but I think with flop raise you are capping your range to draw heavy bluff hands like A7s and A3s as you mentioned and made sets but also you are inflating the pot for no reason.

33 doesn't block any of his calling range. If he had a set, straight, or two pair, he would call down 3 streets. I don't know what your cold call range is but I would think a hand like 67s is a better bluff. It makes it less likely your opponent has 78, 65 or 66. I think the turn barrel is ok because 33 still has some equity, but I would give up on the river.