这个夏天我们离开了这个夏天我们相爱了
[zhè gè xià tiān wŏ men lí kāi le zhè gè xià tiān wŏ men xiāng ài le]
This nickname suggests that a relationship began and ended within the span of one summer. It reflects nostalgia, possibly bittersweet memories of fleeting love during summer time.