爱你家的大姨妈
[ài nĭ jiā de dà yí mā]
In a playful manner using menstruation to mock someone's affection, '大姨妈' ('Dàyímā') means 'Big Aunt' which is used euphemistically in Chinese slang culture to mean a woman's menstrual cycle. The user probably uses this net name playfully, or possibly ironically expressing annoyance or acceptance towards something unpleasant.