Four-word idioms describing swallows

Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying, Yingying Blue Yan belongs to Yan 'an poison Yan 'an poison Yan burns the nest Yan's nest flying screen Yan's nest screen Yan's nest screen Yan's nest screen Yan's nest guard screen Ying guess Yan's jealousy Yan's jealousy Yan's companion Yan Yan's companion Yan Yan's base Yan's nest is on the screen.