piggy in the middle

剑桥词典

[ 不可数或单数名词：没有复数形式的名词 ] (US keep away)
a game in which two people throw a ball to each other over the head of a person who stands between them and tries to catch it
小猪站中间，过顶传球（两人相互向对方扔球，另有一人站在中间试图抢球的游戏）
[ 可数名词：有复数形式的名词 通常作为单数使用的名词 ]
someone who is in a difficult situation between two other people who are arguing
（夹在争吵双方中间）左右为难的人 返回 piggy in the middle