On the other hand, if you think you're actually more fun to have sex with than you seem, then you might be more accurately representing yourself by changing how you seem.

If good mathematicians are believed to wear the yellowest shirts, and you think you are the best mathematician in your class, and at the moment your shirt is only pale yellow, then you would not be deceiving anyone by changing into a very yellow shirt. You might be wrong in your appraisal of your mathematical skill, and as a result you might signal a falsehood; but this would not be deception.