In the post-Mythal scene, I would not describe her as "talking p*ss". She really thinks that she's right, and she's really scared of losing her love.
However, if you want something that does make that Bull banter look hypocritical:
(If Inquisitor is in a relationship with Solas)
Sera: So, you and the Lady Inquisitor. Interesting.
Solas: Your interest is not my concern.
Sera: That's all right, because I meant boring. The elf always takes the elf so that banging bits will mean something.
Solas: It is not a topic for discussion.
Sera: Oh, come on. Drop 'em and rebuild the empire. Phwoar!
Inquisitor: Sera! No more!
Sera: Hmph! Fine. Whatever.
Solas: Don't concern yourself, vhenan. She is… apart from herself.
Or
Inquisitor: (Laughter) You're ridiculous.
Sera: Not me. It's him! And you.
Solas: Only one of us is looking sad and foolish, Sera.
Sera: Oh, go twang your ears!
I mean, it's in character, but the difference is that she gets on with Bull and not with Solas. I guess you only "don't talk p*ss" if you like both the people in the relationship...