不爱我你脑袋被门夹了
[bù ài wŏ nĭ năo dài bèi mén jiā le]
This is a playfully threatening username that can be translated to 'If you don't love me, you must have your head caught in a door.' It expresses a lighthearted way of showing strong feelings toward someone. The humor lies in the exaggeration and hyperbole used to emphasize the intensity of one's emotions.