...I can totally see a frustrated Kirk spin a yeoman around so he can use their back as a flat surface.
On another subject, I assume we've covered what an insanely (literally) boring job Helm and Navigation must be 99% of the time. maybe Sulu can watch movies on that weapons viewscreen thing he has tucked away.
I actually read that a US general did use a soldier's back as a writing desk. Gustave Albert Schurmann (1849-1905) wrote an account of his Civil War experiences. When he was riding as an orderly for General Phil Kearney (1815-September 1, 1862) he had to bend over and let the general use his back as a writing table at least once. Of course Kearney needed take every advantage he could to write clearly, since he had only one arm.
As for helm and navigation, it would have been better if there was a rec room off the bridge that they could be summoned from if there was need of them. If a typical voyage lasted days and was in a straight line from star to star, the ship's position would need to be checked periodically to see if it matched the planned course, and any required course corrections computed and made. And that would be all to do for days at a time unless something unexpected happened.