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