Two situations
With clients: What I do, so I can control them, and avoid their naughtiness
With ideal partner: of course both kinds of foreplay as I want to enjoy the time we're together.
Of course yes, as I'm not cup of tea for everyone. That's good to have a clear point rather than telling me in the last minute that they don't like me.
Reasons: not their cup of tea, or not their regular mls.
You can search for the penis ranking, but I think the rank of Persian and Italian might not accurate, or maybe it's just my lack of experience.