Sorry, this is way too broad of a question. The spectrum of crossdressers/sissies is really wide, and the motivations are diverse. Some panties and stockings to enhance the moment or complete transformation? What do you define as the line to a "real" crossdresser/sissy? (Trick question. No one gets to decide except the panty wearer and perhaps the mistress.)

All my sissies anywhere in the world are the prettiest gurls. I will fight anyone who says otherwise.
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I've broken all my toys. Would you like to be broken?