This is a tough one to answer, since "sexy" is basically part and parcel with considering something "porn" in my brain. There are lots of ASPECTS of lots of different pieces I appreciate - imagination, craftsmanship, humor, commitment to the bit - but it's hard picking out anything that really stands head-and-shoulders above the rest in that regard.

I guess I have a couple of potential answers? The first is Frank Frazetta's "Egyptian Queen". I've mentioned before that my dad had a collection of Frazetta prints from his college days, as well as a book collecting dozens of his better-known illustrations, and this was always one of my favorites. Setting aside the uncomfortable racial overtones that defined so much pulp sci-fi/fantasy illustration from this era, every time I look at it I find something new to appreciate. Frazetta was decades ahead of his contemporaries in the way he rendered female bodies - often lithe and athletic, but just as frequently soft and sensuous, with realistic and alluring distribution of fat throughout their bodies. He also understands light better than possibly any mother fucker who ever set brush to canvas, and his color palettes - made up of browns, greys, oranges - feel more vibrant and alive than any amount of hypersaturated technicolor films you could name. Frazetta was probably my first exposure to the idea of porn being something that could live side-by-side with a fanatical devotion to Craft.

The second is this very stupid screenshot I took of my character's name from the first time I played DrPinkCake's Being A DIK and realized it'd be very very funny for all the women to cry "MURDER MAN" in the throes of pleasure. Being A DIK, compared to a lot of the other fare that finds its way onto @zippity, is actually an extremely competently-produced porno VN, featuring good-quality, well-posed models, high-quality renders, competently-animated sex scenes, and writing that is always serviceable and occasionally pretty funny. However, for all that, when you name your main guy Murder Man, all of that effort is transformed into pure farce. I've always kind of appreciated that as a lesson, not only for my own amusement but also for the stark reminder that sex and sexuality is inherently pretty goofy and you need to be able to work with that.

Hopefully that serves as an okay answer!