" let sleeping dogs lie "

 [ "let sleeping dogs lie" ]

1: it means "don't bring up an old subject or trouble."

  * e.g.,  ... 1: What about that time when I shagged his girl? 

 [ "Let sleeping dogs lie." ]

1: -Prov: Don't be a trouble maker ,let the fuck alone it's gunna beget trouble.

  * e.g.,  ... Jill: Should I ask the boss if he's upset at my coming in late in the mornings? 

 [ "Let sleeping dogs lie." ]

2: -To not talk about things which have caused problems in the past, or to not try to change a situation because you might cause problems.

  * e.g.,  ... Jane: If he hasn't said anything about it, just let sleeping dogs lie. I thought I would ask Jill if she wanted me to pay her back right away, but then I decided to let sleeping dogs lie. 

 [ "Let sleeping dogs lie" ]

1: avoid interfering in a situation that is currently causing no problems but might do so as a result of such interference.

  * e.g.,  ... "It's best to let sleeping dogs lie and not bring up old arguments that could cause unnecessary tension in the group."