The Girl Can Drink, by jericho – Backstreet Boys [Archive of Our Own] | https://archiveofourown.org/

“You’re pretty, though,” Howie said.

“That does not make me feel better right now. And look.” AJ slid the bathrobe off his shoulders, letting it fall to his waist. Howie looked away.

“No,” AJ said. “No, look.”

Howie turned slowly, cautiously, and peeked at AJ. Tattoos bled down AJ’s arms, a dragon one crawling up his back. Exactly in the same spots where AJ had always had tattoos, except now they were on a woman’s body.

Howie extended his hand, looking like he might touch them, and pulled it back. “Wow.”

Source: The Girl Can Drink, by jericho – Backstreet Boys [Archive of Our Own] | https://archiveofourown.org/

Sometimes one just has to dip one’s toes back into (very) old fandom waters. This is still one of the best turned-into-a-girl fics I’ve ever read.