So much of our every day lives involve interaction with our mates. Everything from "What do you feel like for dinner?" to "can I put my thingie there?". You phrase each interaction in the way that you think your mate will be most receptive to. Mrs. WI is sexually conservative in her actions but does not balk at hearing off the wall suggestions. If she were not amenable to off the wall stuff...I wouldn't be Mr. Mrs. WI, that's for sure. I'm quite goofy. A typical conversation surrounding the introduction of a new sexual idea may sound something like this:
me: You know what I've been thinking about?
her: I can't wait.
me: When we're masturbating each other, you know how much I love to cum on your tits, right?
her: Yeah, I think I've noticed that.
me: How would you react if I came all over your left tit, cus you know that's my favorite, and then licked your nipple while I fingered you to an orgasm?
her: I don't know about that. It seems kinda gross. I don't think I'd like it, but I would probably get over it if your fingers were making my pussy feel really good.
me: I've come close to doing it in the past but chickened out at the end, but I've definately thought of it.
her: I just bet you have.
me: I think I'm kinda turned on now.
her: Go figure. I think you should think about painting and maybe you'll get turned on to paint the living room.
If Mrs. Jax wouldn't appreciate the blunt approach, maybe you could bring up the idea as a past thought. Like "that felt so good when you were fucking my face with your pussy...I could almost feel your hands grasping my hair and pushing my mouth against your clit." or "your pussy looked so good when I pulled my cock out of it and I saw my cumshot running down your lips, it was all I could do not to go down and lick you clean, but I didn't know how you'd react" . You never know, she might say "you should have".
Do you watch porn together once in awhile? You could comment on an interesting scene. One of my favorite lines is "Oh my...that looks like it just HAS to feel really good!".
Just a few ideas. But the key is understanding how she prefers to communicate and tailoring your conversation to that so she feels comfortable discussing it.