Maximizing value from a turned flush OOP

[SheepSuit]

I am not going to provide a hand history, because it's more of a general question. Assuming our opponent is a standard, decent, slightly passive player. We raise our opponent calls IP. We flop a flush draw and c-bet, he raises, we call. Turn = flushcard. What now? I tend to always lead, but it turns our hand face-up. But I think if we check, he will almost always check behind and we'll miss value.

Your input please! What possible lines work best for you? Should you 3bet the flop almost always in this situation?