Read it last night and liked it quite a bit. I was a bit worried at the beginning from some of the flowery language, but I either got used to it or it wasn't as prevalent as the story went on. I appreciated the constant attention the son had towards his mother's figure, which kept up the sexual energy even when there wasn't a lot happening on set. The payoff around the 3/4 mark (after the cellar) was satisfying, and overall I felt the take on this haunted house reminded me quite a bit of American Horror Story S1 and Haunting of Hill House, both of which I love.
As an erotic story, I do wish the ending had more of a sexual focus than it did, though if the intent was more to create a cohesive story with erotic elements then it more or less succeeded. Will definitely consider going through your other stories as well now to get a better sense of your style.