We haven't played in ages, but we consider kissing an act of affection, rather than something sexual. With that mindset, it's something we keep for us.
Contrary to Tina and Bob's comment about it being silly—though not to say we're right and they're wrong—we feel sex is just sex, while kissing is so inherently intimate, it's best kept between us. After all, don't most prostitutes have a "no kissing" rule, basically for that reason?
Then again, part of why we feel this way is due to a situation we dealt with in the past. A guy we used to play with—and whom Mrs. LC freely kissed because it added to her enjoyment—grew so emotionally attached to her, to the point that he felt he should have access to her any time he wanted, that we had cut things off—and lost a good friend in the process. We won't allow that to happen again.
Since you don't have kissing to "heat things up," how do you begin your playtimes?
"They may call me a rube and a hick, but I'd a lot rather be the man who bought the Brooklyn Bridge than the man who sold it."