“M an cannot live by a Strand tote bag alone,” said Josh Peskowitz, the men’s fashion director for Moda Operandi. And stuffing our pockets with cellphones, cables and AirPods starts to get unwieldy, especially in the summer.

Enter the petite man bag, but don’t call it a “murse” (a portmanteau from “man purse”). “It’s a fashion version of the bag that Indiana Jones wore under his leather jacket,” Mr. Peskowitz said.