ichidan verb
relate at length; dwell on eloquently; expound
Used when someone talks about something in great detail, often at length and with rhetorical flourish. Can carry a slightly negative nuance of going on and on.
彼は自分の成功体験を延々と述べ立てた。
He expounded on his success story at great length.
会議で持
I got fed up with the person who kept expounding his pet theory at the meeting.