Disclaimer: Gossip Girl and it's characters/events/etc. belong to Cecily von Ziegesar, The CW, and whoever else may have a claim on them. This work has no monetary value and is strictly for fannish purposes.
When Chuck was thirteen he lost his virginity to Georgina Sparks in one of the least sexy encounters of his life. When Chuck was fifteen he lost his other virginity to a high-priced male prostitute in a city where few people spoke English, let alone knew the significance of the Bass family name. The man was light featured for the area, with light brown hair and eyes and skin that was practically Caucasian. If Chuck slipped and called him "Nathaniel" a few times, he didn't care.
When Nate was sixteen he lost his virginity to Serena Van Der Woodsen as Chuck looked on, taking pleasure in seeing two such beautiful people together. Once Nate did that, it was easy to convince him to fool around with the girls Chuck brought back to his suite, and Nate was normally too drunk or high to notice that sometimes the hands that brushed his sides weren't female or that Chuck's eyes rested on his face for minutes at a time.
When they were seventeen, "bromance" became a buzzword among the girls, allowing for Nate to feel that much more comfortable cuddling against Chuck in public even when he wasn't stoned. Chuck hadn't thought it was possible, but suddenly everyone found the two of them together even hotter. Chuck's bed was rarely empty, except when the girl's stumbled off in the early morning and he found that Nate had crawled onto the couch (he was convinced there was some fetish at work, there).
Later in their junior year all of Chuck's careful planning fell apart, as Nate was so far beyond comfortable with even being in a room with Chuck, let alone allowing Chuck to touch him in increasingly intimate ways. He raged, he fucked, he drank himself into a Nate-less oblivion, he stood awkwardly in Blair's elevator searching for something to say.
In a few hours he would be standing with the girl that he'd somehow let come between them, staring at Nate giving a smile that used to belong to Chuck to one of Brooklyn's only friend, as if he weren't slumming it or rebounding. Serena's problems wouldn't last forever, though, then his attention could return to Nate--and God help that little camera-toting gold digger.