There aren't real rules because rules shouls be clear and simple that's to all that make thread games You just have to give the character above a nickname. Just don't make it too offenssive.
Let's start of with mine
Tryst or TB
(Big City) Cowboy, Smoker, Curls
Firey !
Activia
Triv, Jacky, Vev'
Orston (Easton+Orson), Moby Dick (whales), Captain
Callie, Aster, Sherry! Just thinking of some random names that suited your character.
BubblePink !
Yukimelon
Narc, Narco or NZ
Zeph or Zephy.
Ace