Just to clarify. You should discuss her likes and dislikes so you are both clear. But I suggested you did not discuss in advance exactly what you would do in a play session.

Let me explain using food as analagy. You determine your wife likes chinese, italian and french food, doesn't mind italian and dislikes mexican. Then you take her out for a meal one night. You dont tell her where. It can be anything other than the mexican. And if you want to try something new like English food you start with something harmless like roast beef before you work up to soggy chips drenched in vinegar and warm beer !!

In my example you would slap her mildy on the face just once or twice then after ask how she felt. Same if you called her slut once or twice. Once or twice gently is equivalent to tip toe in the water if we are talking about an unknown. But of course ideally you discuss likes before. A good way maybe is to watch bdsm porn together and as you watch ask .. how would you feel about that or that.