"吊胃口 (Diào wèikǒu)" literally means "to hang the appetite." The phrase comes from the idea of tempting someone's appetite by showing or offering something delicious but not letting them eat it right away. It's used to describe teasing or keeping someone in suspense, creating anticipation.
For example:
Tā zǒng shì diào wèi kǒu, gǎo de dà jiā dōu hěn qí dài jié guǒ.
她总是吊胃口,搞得大家都很期待结果。
She always teases, making everyone eagerly anticipate the outcome.
Source:eChineseLearning