In January 1920, when Prohibition went into effect, the demand for flasks was so great that manufacturers couldn't keep pace. Devoted tipplers pressed baby bottles into service and filled hollow walking canes and faux books with spirits.

A century later, as we stare down another, colder season of coronavirus-induced social isolation, the humble flask is undergoing a resurgence.

Pleasingly pocket sized, leakproof and designed expressly for covert sipping, flasks confer espionage-style savoir faire to public drinking in a way that the cumbersome water bottle, with its wholesome connotations, can't even hope to rival.

Stanley, a purveyor of stainless-steel portable beverage ware since 1913, has seen a huge increase in sales of its Classic Easy Fill Wide Mouth Flask 8oz ($25) during the pandemic, the company said. At the flask online superstore Flasks.com, "smaller quantity orders" have risen sharply.

"Based on that, we can conclude that generally more individuals are purchasing and using hip flasks during the pandemic," said owner Chris Barton. The Economy Hip Flask ($3.56) means even the cash-strapped can join the walktail party.

Joe Derochowski, a home industry adviser at market research firm NPD Group, pointed out one advantage of the flask. When the pandemic hit, sales of margarita glasses went up 191% industrywide — presumably for virtual happy hours. "This time around, people might be looking for closed containers that won't spill on their laptops," he said.

If you're an outdoorsy type, or have ever served in a wedding party, you possibly already own a flask. I knew I did … somewhere, though rummaging for it was hardly worth the effort: a delicate silver-plated "ladies' flask" that held 2 ounces at most, if only I could unscrew the top, which was hopelessly stuck to its grooves by time and grime.

By then, I was so taken with the notion of a flask-fueled stroll with a friend that I had no choice but to find a replacement. Online browsing was an evening's pleasure all its own.

My requirements were 8 ounces and an attached cap. I was hugely tempted by the Georg Jensen Sky Hip Flask ($69), a minimalist, stainless steel sculptural number with a svelte leather handle securing the cap to the base, but it holds only 5 ounces. At 1stdibs.com, I pined for a 19th-century silver-plated flask with attached cap and black-and-white leather cover that doubles as a cup. But its $296.32 cost and 4.9-ounce capacity ruled it out.

In the end I bought two flasks, both from Stanley, one for myself, one for whoever deigns to join me. Stanley's Master Unbreakable Hip Flask 8oz ($40) is slightly contoured, to match the curve of the wearer's hip or thigh, and though slightly shorter and squatter than the Classic Easy Fill, weighs slightly more, giving it the pleasing heft of a heavy-bottomed cocktail glass.

Public drinking remains banned in all but 11 states. But during the pandemic, enforcement of the laws has relaxed — depending on the neighborhood and who's doing the drinking — as long as you sip discreetly.

I invited a friend to come by on a Tuesday evening. That afternoon, I mixed the equivalent of four Manhattans, decanted them (sans maraschino cherries, which didn't fit) into my new portable containers, and stuck them in the freezer.

Nothing can replace the cozy pleasure of intimate conversation at a dimly lit bar. But from our park bench, the city's lights twinkling before us, I hardly felt put out. And I liked not risking the health of essential workers just so I could drink with a friend.