He hasn't been a virgin in the sexual sense in so long he genuinely can't remember what it's like. Not that he thinks he lost it early---in fact, he was a bit of a late bloomer---but due to his incredible lifespan it was, literally, so long ago it's difficult to remember. (When he does remember the actual act, he generally wishes he hadn't. There was so much awkwardness, confusion, and general embarrassment; he likes to pretend that first time never really happened at all.)
He's always known what sex is and basically what it feels like. Like, how a person always knows what chocolate tastes like or that bananas are banana-shaped. A person had to see a banana for the first time or taste chocolate once to actually know, but it happened so far in the past that they can't remember a time when they didn't know.
He wants to explain this to Martha one day (she has another one of those ridiculous lists of questions and he's sure she's taking notes), but he thinks that might be too simple a way of describing losing his virginity. After all, copulation is so ridiculously important in human life that he imagines it really should be more of a focus to him considering how much time he spends with humans. As it is, he simply can't figure out how to make it interest him. Sweaty, groaning, messiness, or a splitting supernova over the Silver Devastation, with the light shooting through the icicles on the trees. He knows which he'd take in an instant.
While he might not "indulge" in sexual acts, he does see the effects of them on those around him. The change they go through once they've crossed that boundary between ignorance and knowledge. He does, after all, tend to pick very young companions, may of whom aren't experienced in many things. Virginity is something many humans cherish, and sometimes they try to prevent its loss. Sometimes they'll wander off with some other person for a while, doing things he doesn't want to think about, and they'll come back changed. A little wiser, a little more knowledgeable.
When Nyssa re-arrived after her time with that boy, he considered asking her what it felt like. Not the act itself, because he genuinely never wished to know, but the changing afterwards. The shift from ignorance to knowledge. He can't unlearn what he knows, so he can never feel that change again. It's a strange thing to want, he figures. To be able to feel that shift again. But, he does.
He wants to know what it feels like to be ignorant.
That stands for more than just with sexuality, of course. He wants to forget what it feels like the first time he lost someone he loved, the first time he lied, the first time he killed someone, the first time his actions destroyed a planet.
After the first time, there are always subsequent times. As with all virginities, he supposes, people wait decades, focus on preventing that one time from being anything but exceptionally important. After that first time, it could happen an infinite number of times, each time becoming less and less important until all that's left is an uncaring, asexual being like the Doctor who could give a hoot about sex. He's been there, he's done that. He doesn't even remember where he began.
He wishes he didn't have a beginning when it comes to the violence and destruction in his past. He wishes he were still preventing that first time rather than sitting, staring numbly at everything he's caused.
Muse: The Doctor (Ten)
Fandom: Doctor Who
Word Count: 605