Rule #1: There is no rule book
Rule #1: Is there a rule book for NOT crossdressing?
Rule #1: Then there is no rule book.
LOLOLOL
Crossdressing happens the first time you place an article of clothing upon your person that is traditionally deemed to be tailored for the opposite sex of that which you were born as. Whether it be a pair of pink socks you stole from your sister because you forgot to do your laundry, or your first pair of knickers you made a spectacularly epic fail at purchasing covertly from Victoria's Secret. Once you crossdress, you make it up as you go. No rules. No boundaries. Forget the concept, you have already shattered any notions of those when you first placed that fateful article of clothing on your body. The idea of a 'Rule Book' for us is like an Olympic swimmer going back to the kiddie pool. Once we break down barriers, we GO! Don't start erecting new ones.
I know that sounded far too serious, as I do understand the humour in the 'rule book' thing. I'm simply adding my two cents. OK maybe it was three.