磨鏡 [－镜]

Jyutping mo4 geng3
Pinyin mó jìng

Definitions (CC-CANTO)
  1. literally: mirror grinding; lesbian sex [colloquial]
Definitions (粵典–words.hk)
  1. 動詞、名詞
    古時​對​女​同性​戀​嘅​暱​稱​，​女體​互相​摩擦​以​取得​快感​，​而​兩者​身體​結構​相同​，​睇​落​就​好似​磨鏡​，​因而​得名
    an old euphemism for lesbians; literally: to grind or polish mirror
  2. 近義詞
    磨豆腐
Definitions (Wiktionary)
  1. verb, Xiamen, euphemistic
    to have lesbian sexual relations
  2. verb
    to grind mirrors