I'm new to game and i have couple of quetions.

So we were out in club dancing so at some point some random girl grabs my ass and i give her a look, like its not nice to do this. She does that couple of times more but problem is that all this time she is dancing with some other guy. What does that mean?

other question is? We are in group on the dance floor where there is couple of girls and guys. So i grab one of the girls hand as she has cigarette pack in her hand and i say lets go. She comes along with no problem, so we are in the smoke room, i neg her couple of times, he laughs. Then her friends came there too, i talked with them also(who's the good and bad girl) We went back to dance floor, still dancing with a group and there's one guy between us and she does not pay much attention to me and i decide to go to dance with some other chick i know from school. Later i see her again and i neg her right away, then she says something to here friend(guy) about me and giggling at the same time. Right after that my friend wants to leave, so we leave and nothing happens. So you could give me some pointers what i did wrong and what i should have done. Im new to this so i would appreciate any help i can get.

Sorry my bad English.

In the first example she was either attracted to you or being dared to touch your butt, for whatever reason by the other guy.

Either way, it is an invitation. Instead of ignoring it you should've went with:

You: "*Grabs her butt back* are we playing tag? "
or
You: "Hey! I usually charge $5 dollars for that. Pay up. I'll take cash, or a drink."

then escalated, specifically befriended other guy and/or isolated from other guy.

In the second example you should have ejected from the set with a suggestion of a #close, at least...You were forced to leave because of your friend, and generally when you're leaving that results in a do or die attitude from both the pua and the subject.

thanks man, that cleared up some stuff for me