Symbolism, Imagery, Allegory
For such a short story, the bed is a pretty big focal point. The girl basically makes a beeline to it when she and the boy come upon the older man's furniture spread all over the lawn, apparently fantasizing about what would happen if they decided to have sex on it:
She turned on her side and put her hand to his face.
"Kiss me," she said.
"Let's get up," he said.
"Kiss me," she said.
She closed her eyes. She held him.
He said, "I'll see if anybody's home."
But he just sat up and stayed where he was, making believe he was watching the
television.
Lights came on in the houses up and down the street.
"Wouldn't it be funny if," the girl said and grinned and didn't finish. (24-32)
Far from being creeped out at finding strangers on his bed when he returns from the liquor store, the older man seems pleased: "'Hello,' the man said to the girl. 'You found the bed. That's good'" (41). It's not clear exactly why this is particularly "good" in the man's eyes, but that bed—and perhaps getting rid of it—seems to have some kind of deeper significance or importance to him.
He mentions the bed again later to the girl when they're dancing. As he breathes down her neck and they dance for the entire neighborhood to see, he says, "I hope you like your bed" (94). It already seems like something sexual is going on between the two of them, and his mentioning the bed only adds to the sense that this guy has sexytimes on the brain.
As with everything else in this story, we don't get a lot of answers about what exactly the bed represents to the characters or the story as a whole, but at the most basic level, it almost certainly signifies sexual attraction and desire, both past and present.