[ninjaunderwear]

Let's say SB is holding something like T[img]/images/graemlins/heart.gif[/img], T[img]/images/graemlins/club.gif[/img] (or any reasonable defending hand without a diamond). MP1 raises and he decides to defend. Flop comes with three diamonds and he check/calls.

When a fourth diamond (a king) comes on the turn, SB has an automatic bet situation. If he is behind, he is likely drawing dead. If he checks, MP1 will automtically bet and SB will have to fold.

This is a perfect opportunity for SB to donk and represent a diamond. There is a possibility that MP1 will fold and SB takes down the pot. If MP1 calls the bet, SB can check/fold or check/showdown on the river. If MP1 raises, SB can easily fold.

It may look to MP1 that SB hit his flush draw after check/calling on a three-flush board and then leading when the four-flush hits on the turn.

But, if we dive a little deeper into the world of SB, it would look more like a flush if SB check/raised the turn. I suppose a read here would actually be more helpful than I initially suspected.