My personal favorite character is Kakashi for sure, I have the right mangekyou sharingan contact lenses lying around, but I haven't used them for cosplay thus far. If I ever do, you'll find the pics here :)
The Sexy Technique is a modified Transformation Technique by Naruto in which he transforms into a beautiful, nude woman (with mists of smoke covering her private parts).
Naruto uses it to distract or win over men. One of his easiest 'victims' for this technique is Jiraiya!
The Sexy Technique is popular in convention cosplay (allowing female cosplayers to crossplay male characters).