[n4rf]

I usually check behind like you did if I'm holding a big diamond. I don't like to bet out because I don't want to be blown off my hand just in case a 4th diamond comes off on the river.

^I dunno if that's correct play.

I actually played a similar hand earlier today where I flopped an Ace high flush on a 3-club flush board. I hit my A high flush on the river when a 4th club hit. My opponent flopped a flush and played it super slow (I had top pair and the nut flush draw on the flop). Had I bet the turn he might have blown me off my hand.