A bitchy female or gay man who throws temper tantrums at the smallest provocation or behaves immaturely when something is not going their way. Also dramatic, self-centered, immature and generally pissed off all the time at everything and everyone.
Philip: Ugh, God! I can't believe I had to sign for your stupid parcel. Don't you know how inconveniencing this is?
Jean: Oh, I'm sorry, your door is only next to the front door.
Charlotte (to Jean): God, I just heard. What a Princess Pissy.
Philip: Oh Jean, is it your birthday this week?
Jean: Yes, it was yesterday
Philip: Oh. Are you sure it's not Monday?
Jean: Erm, yes. It was my birthday yesterday. That's why there is birthday cake on the table.
Philip: Oh, I thought the birthday cake was like a pre-birthday cake. I had you down as a bit of a birthday princess. Well 'Happy Birthday!' anyway.
Charlotte (to Jean): Hmm, so no apology, card or present.
Jean: That's Princess Pissy for you.