could (do something) standing on (one's) head

could (do something) standing on (one's) head

Is able to do something with very little or no difficulty, or complete or accomplish something 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 could do this level of math standing on his head.

See also: could, head, on, standing

Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.

can do something standing on your head

If you can do something standing on your head, you can do it very easily. All the secretaries here can do the job standing on their heads. She has been playing gigs for so long she can do it standing on her head.

See also: can, head, on, something, standing

Collins COBUILD Idioms Dictionary, 3rd ed. © HarperCollins Publishers 2012