What do I do if she...

So there is this girl and we have been through alot together
(Close Friends,Going Out,Breaking Up,Getting Back together,getting mad at each other,getting intimate,sleeping together(literaly sleep and cuddle, not sexually) and everything inbetween.

Awhile back she said she doens't want to hang out/be together/see me for a while that I'm too boring but she still doesn't want to never see each other again (I assume she still has, hopefully, feelings for me and wants to be friends again)

The part I bold underline and colored is what I'm talking about. We ar eboth going to be at the same New Year's party and possibly spending the night.

What if for some strange reason she wants to just lie down again, maybe shes drunk maybe she's lonely and wants to feel it again, I don't know.

But if she does try to lie down with me and cuddle do I refuse or just go with it and lie down with her???

Well if you continue to make yourself available to her whenever she wants you, she'll continue to use you as her play thing and throw you down when shes done. You sound like a really nice guy who doesn't stand up for himself. Dont let her use you like that. Yeah she may turn away from you forever once you let her know how you REALLY feel about the way she comes in and out of your life, but you must stand up for self or everyone will walk all over you.

You let her tell you to your face you are "too boring??" You WIMP! Don't stand up for that sh#t! Either let her go or tell her to quit treating you like that.
I think I have a plan for you. If, at this party you see her and she wants to cuddle, you can say "I'm not sure, are you gonna be an a$$hole again and call me "boring"?" If she tells you to p#ss off then so what? If not then cuddle with her and don't talk very much and let her whine "why aren't you talking?" Silence really drives them crazy.
Good luck. But i would not waste much more time with her after this night anyway.