How could I make a move

[soundcloud]Ok, so I've been in my relationship for 10 years. I've always had a crush on my MIL. Ive also felt that she desired me by the way she wud flirt. She has always flirted a bit and I never let her know how much it turned me on. I never reacted . But the last year or So, I've started to flirt back. Nothing big jus a lil touch when walking by. Well one evening at her place when I was at the table she came up behind me and put her huge tits against my back for a few seconds while reaching for something. I knew this was intentional as there was lots of room on both sides of me, it was amazing. The next morning I walked by her room and seen her waking up so I walked in and gave her a peck on the cheek and walked out. She never said anything about it. Since then tho It seems she has distanced herself from any flirting, which makes me feel like now that I've shown interest she has changed her mind. I jus don't know how to read it. I'm scared to ask her as she may jus get angry or something. Any advice on how to take this to another level other than jus asking her? What are some good ways to make subtle moves?