我是你妈的儿媳我是你妈的女婿
[wŏ shì nĭ mā de ér xí wŏ shì nĭ mā de nǚ xù]
This phrase uses humor with an offensive expression; literally it translates to 'I'm your mom’s daughter-in-law and I'm your mom’s son-in-law', expressing an unconventional relationship which doesn't exist normally.