What should I do about my cats?

It sounds like Sammy is just playing. So long as they do have some "down time" and are willing to sleep together or near each other, I wouldn't worry. Let Tink have her own space, some cats just don't like to be keyed up all the time. Make sure she does have her hidey-holes when she needs them and if she sounds like she needs someone to rescue her, simply break them up and let her be.