裙下之臣胯下之宠
[qún xià zhī chén kuà xià zhī chŏng]
The term '裙下之臣' (subjects under the skirt) and '胯下之宠' (favor beneath the waist) are often used in romantic or flirtatious context, referring to men completely submitting themselves to their beloved, especially women, showing a state where they would do anything for love.