耳鬢廝磨 [－鬓厮－]

Jyutping ji5 ban3 si1 mo4
Pinyin ěr bìn sī mó

Definitions (CC-CEDICT)
  1. lit. to play together ear to ear and temple to temple (idiom)
  2. fig. (of a boy and a girl) to play together often during childhood
Definitions (Wiktionary)
  1. phrase, idiomatic, of a boy and a girl
    to have a close childhood relationship; (of a couple) very intimate; deeply in love