Have you ever seen this kind of teacup set which combines two different cups?
What we call this teacup set is 聞香杯 (wen xiang bei) in Chinese, it is hard to find a noun to describe it, perhaps you can say: teacup set for fragrance smelling. The teacup set is used for smelling the fragrance of Oolong tea. (sounds like tongue twist sentence)
You may have a question, why can't we just use normal cup? The reason is Oolong is famous for its fragrance and the normal cup can't keep the fragrance because of wide rim and shallowness.
How to use the teacup set?
First, pour tea in the taller cup and covered by shallow.
Second, put the set upside down, like below picture. If you use the correct way, the two cups will suck each other.
After for a while, use one hand to pull the taller cup, tea will be poured out in the shallow cup. smell the fragrance of Oolong tea and taste Oolong tea.
Try to use the teacup set, you will find difference fragrance of Oolong tea and have more fun enjoying tea.