Hand #1:

You have Td8d in the SB in a 3-handed $30/$60 online game against 2 reasonable players...

Pre:
BTN raise
SB (you) calls (3-bet is ok here too, and the postflop play will differ significantly if you do)
BB calls

Flop:
AKJ rainbow, one diamond

Checks around.

Turn 7d

Obviously you can't fold here no matter what. But do you bet, check/call, or check/raise?

Check/raise is the worst option because it's spewing from behind in a situation where the opponent is unlikely to fold. Maybe can be a good NL tricky play, but at limit this would be horrible.

And while check/call is reasonable, I recommend betting in this spot.

But why? Isn't betting also spewing, given the 3 coordinated high cards?

No. Because there's actually a decent chance both opponents will fold. Let's look at each one....

BB could have almost anything, including a lot of hands which completely miss this board (basically two cards 9 or under). Even with a Q or T (something like Q8, T6, etc), you are unlikely to see a call in a pot of this size. You're likely only getting a call from a pair or better here.

And the button? His check-back on a AKJ rainbow flop is a HUGE clue. It means he hates the flop. Very few hands check that back, due to the straight possibility on the turn. Maybe QT does, hoping to trap, but even AA/KK/JJ won't typically want to give a free card here. The rainbow flop also means that there wasn't a flush draw that the player wanted cheaply. For example, had it been AKJ with two spades, you could argue maybe the button has 6s7s. But not here. This check back almost 100% indicates a miss.

Betting from the SB on the turn looks strong because you're firing into 2 players with 3 high cards on the board. This will negate some of the skepticism that you don't have big cards due to your lack of 3-bet pre. You could easily have something like J7 here.

The bottom line is that a double fold is likely enough to be worth firing. And if for some reason you get called or raised, you still have outs to a queen or a diamond.

Now, is this an advanced play to bet a fairly big draw into 2 players when it checks around on the flop? No.

But there's many other cases where you should NOT do this. For example, say you had the Ts8s in the BB, and the button raised pre, the SB 3-bet, you called, and the button called. There it is almost certain that one of the two hit some of the AKJ board, so you should NOT bet if it checks around the flop. There you would check/call, as betting is just spewing into better made hands.

Much of limit holdem is knowing when your semibluffs will work, and when they will just be spewing money when a dog to win the hand.