Correct

横插一杠子

/ héng chā yī gàngzi / 
Strokes

Example

Definition

poke one's nose in sb else's business; interfere flagrantly; butt in

1
Rénjiā
人家
liǎ
俩
dōu
都
xiāngài
相爱
le
了
  
,
nǐ
你
gànmá
干吗
héng
横
chā
插
yī
一
gàngzi
杠子
  
!

They're already very much in love. Why did you have to butt in?