I volunteered to take shrimp and dip to a casual party. I have two bags of Costco's large size frozen shrimp with tails on, but otherwise peeled. The dip is handled: DH's favorite consisting of Heinz chili sauce with added horseradish and lemon or lime juice. The cooking is my problem. I want them to be sort of straight. Do I insert a toothpick in each one before cooking and then remove it? Is it better to steam them or to barely simmer? Do I put flavorings in the water and if so, what? I have cooked shrimp in many ways, but they always come out curled up. In the prepared party trays I see, the shrimp are straighter and I want that look. Can you help me?