she might be testing you to see how much of a man you are, or she might just be a bitch, try using an ancher, an ancher can be a touch- you could touch her ear or shoulder, whatever everytime your about to make her orgasim or when she's laughing her head off at somthing you said, then when shes in a shit mood just touch that ear and her subconscious mind will turn her legs into jelly and she'l forget what she was pissed about.