少年不懂姑娘那七天的痛
[shăo nián bù dŏng gū niáng nèi qī tiān de tòng]
'Teenage Boys Don’t Understand Girls' Seven Days of Pain' implies men's lack of understanding about women's physical discomfort during menstrual periods. The 'seven days' specifically refers to average time range of menstruation in female.