Couples who seem to have the most passionate and sexy of relationships tend to also have ways of keeping their sex lives in peak shape by doing the things that most other couples haven't done in a very long time.
For example, I know of a couple who has been married for over twenty years and their sex life is still as hot and passionate as it ever was. They "make out" in their driveway and admit that a part of the thrill for them is the effect it has on the neighbors.
Basic to all "naughtiness" in sex is the element of thumbing our nose at the rest of the world. Breaking rules, after all, is a social act: We cannot be "bad" or "dirty" unless there is a society out there to disapprove... and to threaten to "catch us" at it. For many of us, the "naughtiest" and most thrilling sex there is, is sex which flirts with public discovery.
For some of us, the very idea of "going public" fills our mind with anxiety. There are those of us who are not comfortable with even the tamest of public affection; who cannot even stop and kiss at the corner without being overcome by embarrassment and guilt. That is called shame, and it is unfortunate that there are so many men and women who experience shame as a result of affection, regardless if it is public or not. A public kiss has a tingle all of it's own; a very sexy tingle. It's a great place to start if you would like to add excitement to your relationship.