to talk a blue streak 口若悬河（成语）
英文释义
(IDIOM) To talk quickly for a long time without pausing.
On the airplane yesterday, I sat next to a nervous passenger who talked a blue streak during the whole ninety minutes of our flight.
昨天在飞机上，我坐在一位紧张的乘客旁边，在整整90分钟的飞行时间里，他一直口若悬河地讲话。