sex and cheating

So ladies, I've got two questions for you:

These are questions I've polled my friends about and we all had such wildly varying opinions, I thought I'd poll complete strangers.  

1.  Without getting too graphic, what (in your opinion) constitutes sex between two women?    In my opinon, it's either reciprocation in sexual activity or when both parties involved agree  that they slept together.  I've been told that this is a 'straight girl' definition by some.  One of my friends said that it's if one of you got naked.  See what I mean?  I'm just curious what other queer girls think.  And please, I'm serious about the not getting too graphic as I blush easily.

2.  The second question is, within the confines of (your own) typical commited relationship, what constitutes cheating? And do you expressly lay out your guidelines and limitations when you enter into a relationship?  Does kissing count?  What about fooling around with someone of the opposite sex? 

Since I think it's unfair to ask questions of you ladies  without answering them, here's my answer:  I am kind of old school in that I like my relationships to be just between my significant other and myself: which means that kissing other people is out of the equation.  I don't differentiant between the sexes in regard to cheating either.  Kissing a boy is as bad a cheat as kissing a girl.  And yes, I very clearly state as much when committing to a relationship.

I'm curious to hear your answers.  Thank you, and cheers!