I thought that my luck was extremely good (for once) and opened 1♥. East passed and then South raised to 4♥ (I had 7 hearts, so I assumed that his raise was a game raise and not preemptive). I was expecting 4♥ to comfortably make (I had seven tricks in my own hand) when I had a rude shock: West bid 5♦. I sort of panicked after that as I had never seen a high-level overcall before. In the end, I chose to bid 5♥ because I was very worried that West might make 5♦ on his hand alone. What should I actually have done in the situation, bid 5♥ like I did, double for penalties or pass and shove the decision to my partner?
(For those who are interested, the full layout was as follows:
As you can see, 5♥ could and should have made, but I made the stupid mistake of trumping West's second-round diamond with a small heart and got overtrumped by East, and so went one down. )