Interesting take on the Monkey's Paw story. Your story succeeded in giving me nightmares last night, so I'd call it successful on the horror front (then again, those horror stories for children collections have always given me nightmares as well, so I may be a poor judge). I was rather uncomfortable with the sexual explicitness of it, but I'm still working on being able to read even extremely mild sex references in fiction without feeling like a terrible person for doing so.
.Yeah, it was weird how sexual it got. It's not a path I walk that often in my writing. But if it gets under your skin, success.