"I feel funny," he said. "Better see if anybody's home."
She bounced on the bed.
"Try it first," she said. (18-20)
From the get go, the girl reveals herself as a little bit of an exhibitionist, since she apparently seeks out the thrill of doing naughty things in public. Here she's trying to convince her boyfriend to play on the bed with her, but he's uncomfortable.
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. (24-30)
The young girl is pretty persistent about trying to get the young guy to fool around with her, but he definitely feels guilty and/or uncomfortable about it. He doesn't outright say no, but he finds an excuse to sit up and avoid making out with the girl on the bed.
"Go ahead," the man said. "It's my yard. You can dance if you want to." (83)
Meanwhile, the owner of the bed (and the lawn) doesn't seem to care what the young couple does on his property or who sees it—he actually encourages them to put on a show for the neighbors by dancing.
"Those people over there, they're watching," she said. (89)
At first, when the guy encourages them to dance, the young girl indicates she's uncomfortable, noting that there are people watching. Wait, where did the exhibitionist from earlier in the story go? You know, the one who was willing to get frisky in public? Now dancing is an issue? What gives?
"Let them watch," the girl said. (91)
Whew—we thought we were going to have to revise our opinion of the young girl and her willingness to do whatever, regardless of who's watching. Although she was concerned at first that people were watching her, here (just a couple of lines later) she's back to her old self, totally comfortable and guilt-free about the fact that people will be watching her dance. Once the guy gives her permission not to care, she decides that she doesn't.
"That's right," the man said. "They thought they'd seen everything over here. But they haven't seen this, have they?" (92)
We're not totally sure what's going on here, but it sounds like the older guy has been the subject of scrutiny before—apparently, the neighbors have already seen "everything" at his house, so a little dancing can't hurt, right? The fact that the older guy has already put on a show (of some kind) for the neighbors means that he and the young couple can do it again without worrying or feeling embarrassed about it.
Weeks later, she said: "The guy was about middle-aged. All his things right there in his yard. No lie. We got real pissed and danced. In the driveway. Oh, my God. Don't laugh. He played us these records. Look at this record-player. The old guy give it to us. And all these crappy records. Will you look at this s***?"
She kept talking. She told everyone. There was more to it, and she was trying to get it talked out. After a time, she quit trying. (97-98)
Evidently the girl wasn't quite as carefree about the encounter as she initially said she was. After, she kind of puts all the weird behavior on the older dude, but there's clearly something about the whole thing that bothers her. It's not clear whether it's guilt or shame about being drawn to the older man or what, but something has clearly stayed with her that she's trying (and failing) to talk out.