I would also suggest doing what Barton said. Make things clear for the people with whom you are trying to meet or carry on conversation. Make them aware that pain does nothing for you, but you like to be tied up.

If you want specific wording, tell people you have a bondage fetish and enjoy being restrained, but that you are not a masochist at all. Most people that know what they're doing and are serious about having a relationship with you will understand what you mean and will not protest.