Your older cocker should be left to deal with the puppy exactly as she is. As long as there is no agression and as long as the older dog is responding to you the same as always then she is doing her job as mentor and role model perfectly. This is exactly what we mean, as behaviourists, by "dominance". The older dog is not responding to puppy behaviour as the puppy is not showing respect. Your older dog is showing that she is secure and happy and play will happen when she is ready and the pup is behaving in manner that befits her place in the household. What you can do to help the situation is bolster the older dog. Of course you want to make a big fuss of a new pup and spend time training and getting to know the baby. That is always good. Just make two or three minutes for the older dog before spending time with puppy. Put puppy on a lead and run the older dog through her paces, praise and release and then spend time with pup. Always put the older dog first, let her take her time to "train" the pup and all should be well. Do not try to make them play together, it will come if you relax.