my cat makes himself gag for attention? unsure how to correct

i’ve noticed that if i take too long to feed my boy cat (2), he will sit underneath my metal bookcase and pressed his throat on the bar, making himself choke/gag(??). i noticed this a few months ago and was extremely alarmed because i thought he was choking on something he found on the ground but no, every time i check, he isn’t stuck, he’s not trapped in any way, he can fully crawl under/over the bar, he just… does this. like he presses his neck on the bar, gags, and then sits there. once i feed him, he doesn’t even go near the bookcase. he has no other strange or even slightly harmful behaviors, just overall a dumb baby. it’s not frequent enough where im super worried but im unsure if i should be. again, i have only noticed this behavior before breakfast/dinner time. does anyone else’s cat do similar things? should i be concerned?