(1S)-2D-(Pass)-3H.
I was the the 3H bidder. We landed on our feet in 3NT. I felt confident that my capable partner would take my 3H as strong and natural, but beyond that I had no idea what he might think that I held.
Our two hands were:
As you can imagine, 6D would go down on a spade lead and spade ruff. You can decide whether, on the NS hands, you would like to be in 6NT but as the cards lie Gib says that 11 tricks are the limit on any lead except the heart J (East holds Jxxx).
We discussed this briefly afterward and partner said he believes 3H to be fit showing but of course some fits are better than others. I was not expecting the 3NT response to my 3H, but I figured if I had spades and he had spades, a spade ruff was a serious danger and so I gave up on the diamond slam. I could see that partner didn't have many points in diamonds, and he didn't raise hearts, so I figured he had something in clubs. So I passed the 3NT.
As I said, we landed on our feet.
My point here is not our brilliant bidding. Rather I was thinking it might be fun, perhaps even useful, to have examples of coping with auctions where we wish we had discussed the meaning but we have not.
Others are invited to contribute examples.
Btw, I agree that my 3H shows at least some diamonds. If I knew we should be in hearts I would have bid 4H, not 3H. If I don't know we belong in hearts, I had better have some diamonds even if we are going to play in 3NT. Presumably 3H does not show the AKQ of diamonds.
And yes, I would like my heart suit to be better for that 3H bid, but what else?