Imagine that you decided that you and your wife should do some thrilling things together. Skydiving is thrilling. You ask your wife if she is wants to go skydiving this weekend. Her answer is likely to be "Fuck No! Are you insane?"
Too much, too soon. On the other hand, indoor mountain climbing, with safety cables attached to your waist, might be as far as she is willing to go. As you two worked your way up the ladder of dangerous sport thrills, she might even consider bungee jumping off a tall bridge. Seeking thrills, like any addiction, requires ever-stronger hits. Note that she could actually skydive this weekend, as nothing physical stops her, only her fear and concern, which are mental states. In order to leap out of the airplane at 40,000 feet, requires at the very least the belief that you can do it—without that belief, you will remain in the safety of the airplane.
Mental stretching is a slow but essential process. The mind must be stretched to view some activity as being at least possible, although not necessarily desirable. Fantasies and roleplaying are the yoga of mind stretching.
I once had an attractive but mentally stiff girlfriend, at least with regards to sex. For example, the thought of having sex in each room of the house was too great a stretch for her. She needed serious mental stretching.
While making love, I told her sexual fantasies, which she responded to with enthusiasm. The fantasies were either my own or stolen from previous girlfriends or based on a movie or TV show we had recently seen. On rare occasions, she came up with a fantasy. As my cock filled her vagina, and as her ears filled with my pillow talk, her mind stretched. From fantasies, we moved onto to my telling her of actual and possible sexual situations. For example, I had read about sexual surrogates, who—as part of a patient's therapy—had sex with the patient. I showed her the article. She made a face as she read it.
Later that night, once I had her sexually warmed up, I mentioned the article again. I asked her how the female sexual surrogate's boyfriend or husband must feel about the sexual surrogate's workday. Her answer was along the lines that he must feel terrible. I agreed that most men would, but not all. I revealed that I would certainly enjoy hearing about her "damn day" at work if she were a sexual surrogate. She instantly repulsed the notion, finding the job degrading and dirty. I explained that the sexual surrogates were not prostitutes (if nothing else, they were far more expensive) and that they performed needed aid. I gave the example of their helping men with sexual problems, such as premature ejaculation. She wanted to know how that problem could be treated.
My answer was that if she was a sexual surrogate (notice how I had just talked past the sale), she would insert his hard penis in her, while she straddle him in the cowgirl position, but she and he would not move. His hard cock would be in her, but no fucking would occur. They would talk about the weather, movies, or restaurants, as the whole point was to let him get used to being inside a woman and not being brought to a quick orgasm; the only movement she was allowed was when she felt his erection soften. Even with no movement, he would probably cum in a few minutes anyway. But with repeat visits, the minutes would grow longer. Eventually, they could slowly move. And, finally, he could go the distance.
I was stretching her imagination. She loved hearing such a story. And she liked how I described the pride and joy I would take in her having such an occupation. An hour earlier, such a scenario would never have occurred to her; now, it was part of her fantasies while I ate her. In fact, she enjoyed this scenario so much that we roleplayed it. All roleplaying starts off fake and stilted, but can quickly transition into an alternate reality, wherein you actually feel that you are not acting, but just being yourself, albeit a different self.
If you haven't engaged in roleplaying, you are missing out on possibly the best sex you ever had.