Alright, I'm jumping in because I just spent a summer deep in this very specific niche and I have THOUGHTS. Everyone always points to the classics like 'Daughter of the Pirate King' or the 'Pirates of the Caribbean' tie-ins, which are fun, but feel a bit... sanitized sometimes? Like, they hint at the debauchery but pull back. If you're truly after that 'slutty pirate' energy—characters who own their appetites for plunder and pleasure without apology—you gotta dig a little deeper into indie romance and some older historicals.
My top rec would be 'The Adventures of Amina al-Sirafi' by Shannon Chakraborty. Okay, Amina herself is a retired pirate captain and a mother, so maybe not 'slutty' in the modern sense, but her past is gloriously messy and the book doesn't shy away from her former life of hedonism and rule-breaking. The romantic tension with her ex, a rakish mapmaker, is fantastic. For pure, unadulterated spice with a pirate, 'Bitten by a Hellcat' by Felicity Heaton has a privateer hero who is... aggressively forward, let's say. It's paranormal, but the pirate vibe is strong. Also, don't sleep on some of the older bodice-rippers from the 80s/90s; 'Sea Fire' by Christine Dorsey has a privateer hero who is constantly getting the heroine out of her clothes, and the adventure holds up surprisingly well. The key is looking for books where the piracy isn't just a costume; the lifestyle of freedom, danger, and living outside society's rules directly fuels the character's sexual agency. That connection makes the romance hit different.