IN THE SECOND EPISODE of “I Think You Should Leave with Tim Robinson,” an absurdist Netflix sketch show that premiered in April, you’ll find a skit devoted to T.C. Tuggers, the shirt “with the little knob on the front.” Utterly insane, the fictional shirts boast a bottle-cap-sized pull-tab at the midsection, which, according to Mr. Robinson’s character, is there “so you don’t wreck your shirt or hurt your hand” when pulling your T-shirt down over your belly. Would anyone actually wear a T.C. Tugger shirt? I hope not. But this silly skit is rooted in a familiar real-life tic: Many men pull on their shirts, just below the...