@dingo24,
Date
She kissed you
we should do it again
can't make it
seeing another guy, getting serious
sniggering and talking about you
It's actually possible that she used you to get the other guy jealous.
It's also honestly not worth worrying about, because you only want to re-date someone you kissed that kissed you because they liked you.
Next time they look down at you, laugh, smile and tell her, so did kissing me get him jealous and get what you wanted? Be careful Karma is a bitch when you use people, turn and smile and walk away.. That will shut her up for good.