I bought this cheap Karambit style neck knife and just realized I don't know how to sharpen it.

It's a mild curve compared to many but still......

I'm edge sharpening challenged by default but this is a new twist all together.

Should I look for some sort of rod shaped stone? Or maybe one of those stones that has a round edge and the other edge tapers to a knife edge?

It's not flat out dull out of the box but it's not what you call sharp either.