standing on one's head
standing on (one's) head
With very little or no difficulty; in a relaxed, carefree, or effortless manner. It took me a little while to get used to this job, but now I could do it standing on my head! You should ask Johnny for help—he does this level of math standing on his head.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
standing on one's head
see under do blindfolded.
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.