to swing by 顺访
To visit casually; to go to a place for a short time without elaborate preparation.
When I am in his neighborhood, I like to swing by my old friend's office for a cup of tea, simply calling him that morning first to see if it's convenient.
到老友所在的街区时,我喜欢顺便拜访他的办公室,在那里喝杯茶,只需事先打电话问他是否方便。