Backtagging: Always welcome!
Threadjacking: Depends of the thread. If it's not obviously okay, contact me first!
Fourthwalling: Ask me first please, but generally it will be yes!
Offensive Subjects: offensive subjects? Intriguing.
Handwaving / Fade to Black: While I'd rather play out things, sometime we have no choice so if needed, yes.
Hugging him: Why not? Don't expect the warmer of hugs in return.
Kissing him: Do you want a bewildered android? If so, why not.
Flirting with Data: Well, you can, always try.
Falling in love with Data: That can't be helped.
Injuring him: Good luck.
Killing him: Contact me first. Data can't be exactly killed like an human.
Mind controlling him: More often than not, no. Only a few kind of mind control work on him.
Using telepathy to communicate with him: No, telepathic power do not work on Data.
Reading his mind: Nope either.
His soul/heart/spirit: There is nothing to be read. No light, no darkness, no good, no evil. Data is a good person, but being an android people who can feel that kind of things will feel no such thing from him.
His powers: Nothing special, except super strength, resistance, intelligence, etc.
Warnings: If he goes berserk, Data is nigh unstoppable. Good thing it very rarely happens.