There aren't any things about sex itself I would find slutty. For me it's the disregard for ones own feelings or that of anothers that would demonstrate a sense of sluttiness. Now there are some things I will not do sexually, but it's not because I think they are too slutty... I just don't like them on the grounds of personal preference.
I think she just overreacted when she claimed "girls who do oral sex are bitches." Apparently she is under a misconception or simply stating a common stereotype.
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen