Jim kicked at the floor of the cave. Six hours. Six long, boring hours before the Enterprise was back in transporter range; with any luck the angry, prison-happy Elarians wouldn't find them first. He looked over at Spock, who was leaning against the cave wall with his arms around his knees and his eyes closed. He'd been that way for two hours, and Jim was pretty sure he wasn't asleep. Right now, though, Jim felt like he needed some conversation to break up the complete boredom of being trapped in a cave.
He took two steps and tapped his boot against Spock's boot. "Hey."
"Captain," Spock answered, eyes still closed.
"So you're half-Vulcan. A hybrid."
A long pause. "You are aware of that already, Captain."
"So, are you fertile?"
Spock's eyes flew open as his eyebrows flew up. "Of course," he answered.
"Most hybrids aren't."
Spock's eyebrows climbed, if possible, even further up towards his hairline. "I'm genetically engineered, and my designers were not idiots."
Jim raised his own eyebrows, now. "I wasn't suggesting they were," he said. "Just that they might not have been able to fix that."
"I know you achieved satisfactory grades in your biology and xenobiology coursework," Spock said. "I see no reason to discuss the choices my designers made about my biology with you at this point."
Jim sat down. "Small talk. This cave is exceptionally boring, in case you failed to notice, and it's either small talk or six hours of tic-tac-toe, Mr. Spock."
"Spare me," Spock said, closing his eyes and leaning his head against the wall again.
Jim frowned and drummed his fingers on his thigh. "OK. Hey, do Vulcans have casual sex?"
"Is that a proposition, Captain?"
Spock opened his eyes again. "Then it depends on what you mean by 'casual sex'."
Jim waves his hands. "Sex. With someone. Without--things. Like, do Vulcans ever pick up a partner in a, a, spaceport tea shop or whatever, have sex, and never see the person again?"
"It is uncommon, but it does happen. More frequently in pornographic material than in reality."
"Vulcans have porn?"
Spock looked at him like he was insane, which: OK, every OTHER sentient species Jim could think of had pornography, so why he thought Vulcans wouldn't... "You all seem so buttoned-up," he said, by way of explanation.
"Vulcans do not have casual sexual relationships," Spock said, after a minute. "Humans often seem to have sex with their friends, for mutual pleasure, with no attachment beyond that. Vulcans do not have that form of casual sex."
"Huh. Because you don't have friends, really?"
"Captain. Vulcans are social beings. But our alliances, associations, and relationships are constrained by our telepathic abilities; casual sexual relationships with associates or friends are likely to form telepathic linkages that are...undesirable and possibly dangerous."
Jim grinned. "So, you're really serious about Uhura, then? Don't get her pregnant, please, Mr. Fertility; she'd have to go on starbase or planetside duty and then who would keep me in line?"
"Lieutenant Uhura," Spock replied -- somewhat primly, Jim thought -- "is a sensible person and it is not any of your affair what reproductive choices she and I have made about our relationship."
"Oh, good, she's got an implant."
Spock looked offended. "I did not say that, Captain."
"You didn't have to. That's what a sensible person would have."
"This is an exceedingly inappropriate conversation."
Jim drew a tic-tac-toe grid on the ground with his finger, and was gratified when Spock rolled his eyes. "Next question! Ever thought about sex with men?"
"Are you going to pursue this line of inquiry for the next five-point-seven-three hours, Captain?"
"Will you be at all dissuaded if I simply cease to answer?"
"Perhaps I shall endeavor to find out," Spock said.
"Spoilsport. I won't tell anyone about your fantasies. Cross my heart."
Spock laid down on his side and closed his eyes. "I am going to sleep, Captain. I suggest you do the same." Jim watched as Spock's breathing deepened, then scuffed out the tic-tac-toe grid with his boot, and stretched out next to Spock, close enough to feel his warmth but not quite close enough to touch.
"Spoilsport," he muttered again, putting his hands behind his head, and feeling sleep overtake him.