If you are in a 5-way unraised pot holding

And the flop comes down

With no info on any players/stacksizes/table image but as a general rule, would you check/bet if you were:

1st
2nd
3rd
4th
5th

to speak and it had been checked to you?

I think 1st or 2nd to speak you can look for a check raise but any later and you have to bet. It is just horrible to flop the nuts and know that almost half the cards in the deck will change this and therefore you can't afford to give free cards.

four other callers? The odds are there's an ace out there somewhere. If an Ace hits the board you're fine (unless it's Ad), a 10 or a Jack and you're getting on shaky ground, a Jack and a 10 hitting is a longshot, but in that case you're screwed, a diamond and you may be screwed. If someone holds ATd or AJd they're a double threat, and a JTd would be a split pot with a chance of you losing to a flush. Most of the hands that are a danger to you are ones that if they were dealt out, they'd probably still be in an unraised pot.

If I was given the chance to be the aggressor, then I'd probably bet like it was a pair of Aces in need of protection. I'd go at least twice the pot, maybe even push. It would certainly be an attempt to buy it right there and avoid all those nasty draw possibilities, but also a decision to make that draw very expensine for anyone who wants to look. If someone calls they have a loser, split, or a draw and I'd throw it to the fates.

in any position.. i bet about 75%-80% of the pot here.. this way someone holding TP, or 2pair, will probably raise me, which then i can re-raise.

no way am i going to check-raise here, as its 5 handed, and i dont want to risk giving away a free card for someone to make a straight and split the pot with me, or worse, a flush to win the pot.

maybe if it was 3 handed or less, then i would go for the check-raise.

This is a great question/example. I think there are many proper ways to play this hand.
First, what are our scare cards? 11 diamonds (flush cards, obviously), 3 Ks, 3 Qs and 2 9s (possible boat for anyone w/ KQ, K9 and Q9), 2 JavaScript and 2 Ts (but really only if we fear a split pot OR AT, AJ (unlikely in my opinion).
That's 19-23 scare cards out of 48. There is a 40-48% chance of one of those cards hitting the turn and a 64-73 chance of one of those cards hitting the turn or river.

How to proceed? (not necessarily in order of preference)
1) Push. Get your money in with the best hand. No more decisions.

2) Bet the pot or a little more. Price out the flush draws.
The problem with #2 is that we have very fishy waters out there and we have seen them call this bet too many times. Also, if the guy with KT calls, the flush draw after him is getting 3-1 or better (proper odds for a call).

3) Big overbet (but not a push). OK, this prices out the draws, but we are committing even more chips and there are many fish that would still chase. We also scare away (possibly) Kx, Qx and 9x who we want to get chips from.
But the biggest problem with 2 and 3 that I see is that we aren't getting enough info from everyone. Let's say we bet 1.5 x the pot and get cold called. A diamond hits the turn. Are we facing Q9, K3 or a made flush? We now have to act out of position with very difficult decisions to make. If we check, we're getting raised. Now what? If we bet we're getting called or raised. Where are we? We announce with our betting on the flop that we don't have a flush. Neither the two-pair or 52d is afraid of us and we can't tell the difference. And the more chips we have committed so far, the more difficult and critical our decisions become.
I think options 2 & 3 should be made from late position. We have a much easier time acting last on the turn and river.
The thing that can help us with options 2&3 (more so 2) is if our bet gets reraised by the Kx or two pair (or even a set of 9s). But if they are going to reraise a pot sized bet....

4) Why not make a weak bet from early position?
If everyone limped PF, there’s 5BB in the pot. Bet 2-2 ½ BB. This disguises our hand very well. It looks like we either a) got a piece of the flop, but not a monster or b) we’re on the flush draw and we’re trying to buy the next card cheap. The flush draws, Kx, Qx and 9x are all are going to call, but 2 pair, set or even KT will all raise this up. Now we have a read on everyone.
If someone has two pair, a set or even KT, they are likely to re-raise. We can now put them on a hand. We are only slightly concerned that they have Ax of diamonds. We can now go over the top and push (getting more chips than an original push). And we are now far less likely to get called by a fish with a flush draw.
Lets say we just get callers. If the turn is a blank, we are golden. Its time to get aggressive and bet big. Its now an easier laydown for the flush chasers and we can still get action from anyone with a moderate hand. If a K, 9 or Q hits the turn, we are fairly confident that no one has the boat because they would have re-raised their 2 pair on the turn.
If we just get called and the turn is a diamond, we bet out small (maybe a little more that on the flop). To everyone else it looks like we hit our flush. Any raisers and we can confidently put them on a made flush. But there is serious folding pressure on anyone without a made boat or Ax of hearts. If we get called, we will probably get called again on the river without committing a lot of chips.

Again, this is a great scenario that demonstrates the complexities of NLHE. What do you think?