could (do something) standing on (one's) head(redirected from could standing on their heads)
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.
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.