A 1940s beach party might conjure images of chaste bathing suits and innocent fun, but even the party people of yesteryear had a few tricks up their sleeves. One of the best: spiked watermelon. It may seem like an invention of the Girls Gone Wild era, but beachgoers have been pouring vodka into their watermelons since Joe Francis’ parents were in diapers.
Times have changed since LIFE photographed this spiked watermelon party in 1948, but the recipe is still as simple as ever: about 3 cups of vodka funneled into a 10 lb. watermelon to spike the fruit itself; or into a hollowed-out rind along with the juices of the melon, to create a punch served inside the fruit. Bonus points for huddling around the melon Kumbaya-style and sipping through straws side by side.
Liz Ronk, who edited this gallery, is the Photo Editor for LIFE.com. Follow her on Twitter @lizabethronk.