How to ask without making a sales pitch

One of the four main sections in the WifeWantsToPlay archive is called "How to Convince Your Wife". It contains 1,704 threads. That title tells us how the forum organised discussion. It doesn't tell us how the women involved felt, and it certainly doesn't make persuasion a good model for a relationship. A common trap in these conversations is preparing the argument before asking whether the other person is interested. The difference between "I've found ten reasons this would be fun" and "Can I tell you about a fantasy without asking you to do it?" is enormous. Try giving the other person room to say the idea does nothing for them. If the answer is no, it is information, not a debate to win. An honest first conversation may end there, and that's a perfectly useful outcome.