A couple of times at parties i get that said to me from, in a joking way.. obviously im not trying to rape them.

Im not really aware that im really touching them.. im quite big and muscular to that may just be why...

Anyway i started just responding in a jokey way like: 'stop grabbing my ass!'

...then she goes and grabs my ass

Now what? ...

Also, say theres a girl whos dressed up as a slut or is impersonating a slutty girl and the man implies the girl will be acting really slutting cos of that, they seem to get turned off... is there a good way to do this without sounding needy and turning the girl off?

You gotta mix your game up with push/pull. Then you won't come off as needy. Try searching for it, I'm sure there's plenty of threads on it.

i would say to her...

" so, No means Yes, right? "

and wiggle my eyebrows up and down

When she grabs your ass:

"Hey, that shit ain't free ya know"

use her own line "stop touching me!"

"Who do you think you are!?"

"At least buy me a drink first! (before grabbing my ass like that!)"