Dean had never intended to tell Rory. But he was drunk, and lonely, and still rather angry about the way Rory had dumped him, which all added up to a very late phone call. He did not go into details, could not have, even had he wanted to, because Rory, at some party with Logan, hung up on him with a cutting "Oh, you've got to be kidding me! Just... grow up, Dean!"
Which left him still drunk, still lonely and angry, but also deeply mortified - although he had been nothing but truthful, if crude: "You know, Rory, when you come you sound exactly like your mother. Taste like her, too. Sweet."
Now he lay back on his bed, chucking the phone into a corner with a satisfying thump. He remembered Rory's taste clearly, not just the taste of her mouth and her clear skin under his lips, but also the dark musk between her legs, a memory that still felt somewhat illicit and new. After all, he had NOT known what she tasted like "down there" for much longer than he had known it, and when he finally did, it had been all he had been dreaming of for years. At the time he had not compared her to Lorelai, had done his best not to ever think of the fact that he was able to do so, but no such considerations held him back now. Almost unconsciously Dean slipped one hand into his jeans and started stroking himself.
Kissing Lorelai had not felt new, or fresh, or like a dream come true. However it had felt illicit, but not because of some remnants of nostalgia, as he had felt for the image of pure, innocent Rory, but because he was engaged and standing in his ex-girlfriend's kitchen with her mother's legs wrapped around his hips and her tongue deep in his mouth. Dean had had sex before, a couple of fumbling times with his ex in Chicago, but nothing had prepared him for Lorelai. She'd been drinking when he came to drop something off, clearly upset about something or someone, and because it could have been Rory he didn't ask, and Lorelai didn't tell, just smiled at him, asked how he was doing, and absent-mindedly played with the frayed collar of his shirt. Then she'd said "This is such a bad idea" and kissed him, clinging to him in a way that left Dean no choice but to kiss her back.
She had his zipper down and his erection in hand before he had properly realized that he was fully aroused, and one moment later Lorelai was up on the kitchen table - "It's not as if we ever eat here" - and he was pushing into her. She wasn't very wet, but he tried his best to hold on long enough so it'd be good for her, too. Only he was hardly more than a boy, and she was still kissing him and urging him on, so when he collapsed on top of her it was only a few minutes after they had started. When he got his wits together enough to make sure he wasn't crushing Lorelai she was smiling at him, a little amused but also conspiratorally, and he had dropped to his knees and spread her legs open with his hands. He had never done this before, but Lorelai was vocal and her hands made sure he found the right spots. It was a strange sensation, a strange taste and feel in his mouth and under his tongue, but mostly in a good way, and he kept going until he felt Lorelai tremble and fall apart.
He hadn't felt guilty then. Especially not when she slid off the table and turned him around and returned the favor. However, when, much much later, in Miss Patty's studio, Rory went to her knees for him, all enthusiasm and little technique, he had to keep his eyes wide open to make sure he would not compare, would not remember the way Lorelai had cleaned him afterwards, talking about a movie she wanted to see, as if he'd spilled ketchup and not semen. It had not been difficult then, he had been too full of love and giddy disbelief, but now, alone in his room, with no Gilmore a part of his life anymore, Dean allowed himself to remember every moment and came with a gasp that might have been either name. It didn't really matter anymore, after all, and they had both tasted sweet.