"Grain in the ear" would be better, provided that the audience knew what the term actually referred to, i.e., an Asian culture lunisolar term.
我自知英语水平不及您，所以相信您的感觉。第一次看到 “Corn on Ear” 时没觉得不妥，似乎和 “Baby on Board” 差不多。
1. Lit. aboard (on or in) a ship, bus, airplane, etc. Is there a doctor on board? We have a sick passenger. When everyone is on board, we will leave.
2. Fig. employed by someone; working with someone. Our company has a computer specialist on board to advise us about the latest technology. Welcome to the company, Tom. We're all glad you're on board now.
(McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.)
1. supporting something While most of us might be OK about interracial dating, some people aren't on board with the notion.
2. working with someone It's a well-financed organization, and it has some well-known people on board.
Etymology: based on the literal meaning of on board (on an aircraft, train, or ship)
(Cambridge Dictionary of American Idioms Copyright © Cambridge University Press 2003. Reproduced with permission.)
if someone is on board, they are working with an organization or group of people A new financial director has been brought on board to help us assess the cost of the project. We hope to have a new doctor on board by the end of the month.
(Cambridge Idioms Dictionary, 2nd ed. Copyright © Cambridge University Press 2006. Reproduced with permission.)
Joining in or participating, as in The department head addressed the new employees, saying "Welcome on board," or The opera company has a new vocal coach on board to help the soloists. This expression alludes to being on or in a vessel, airplane, or other vehicle. [Colloquial; second half of 1900s]
(The American Heritage® Dictionary of Idioms by Christine Ammer. Copyright © 2003, 1997 by The Christine Ammer 1992 Trust. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.)
2. Ready to participate or be included; amenable: The entire class was on board for the excursion to the park.
(American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.)