I first saw “The Spanish Leather” advertised in a mail-order catalog from Eric Stanton in the early 90s. Unfortunately, I didn’t order it and had to wait quite a few years until I found a copy for free online. At which point I jerked myself raw, needless to say.
The author is given as R. Ironwood but the artist is clearly a guy that went by the name of RAMM and did BDSM art for Ceturians magazine. He also did a 64-page BDSM publication called “House of Bondage”. I’ve only seen two other images done by him. I think his main stock-in-trade was maledom BDSM so “The Spanish Leather” is a departure for him. Maybe Stanton wrote it and RAMM illustrated it?