"spread a blanket" is correct and usable in written English.
You can use this phrase when describing someone laying out a blanket on the ground or on top of another surface. For example, "The park was blanketed with a sea of picnic blankets. Jimmy spread a blanket on the grass and began to set up for lunch."
Others without nationalistic props spread a blanket on the snow.
Marina would spread a blanket under a tree and lie down with a book.
Park, unload the picnic basket (Andy Warhol packed it, so lots of soup) and spread a blanket.
They arrived early, spread a blanket on the grass, and waved at John, who was sitting at a picnic table, writing in his journal.
Katie Porter, who gardens in Mendham, N.J., was shocked when visitors spread a blanket on her lawn and began to set up a picnic lunch.
The allusion seems to be to spread a blanket over the head to obstruct one's figurative sight, similar to the origin of hoodwink; other speculation goes as far as to suggest pulling a person's hairpiece over his face.
My eyelids flutter each time she taps a needle into me and when she's done, spreads a blanket across my body.
In villages and parks from Cedarhurst to Montauk, music comes pouring from gazebos and band shells, free for the enjoyment of anyone who pulls up a lawn chair, spreads a blanket or finds a spot on a park bench.
The Snyders watched most Redskins games at home, spreading a blanket on the floor as if they were tailgating.
Among other things, these are the perfect beers for barbecue, for spicy Thai, Indian and Chinese food, for mustardy hot dogs, softball games and spreading a blanket outdoors hell, for summer in general.
Love overspills boundaries, whether spreading a blanket on a sleeping child or covering the desert with clouds.
