Would you believe me if I got angry and stubbed my cigarette out on her arm?
Are you for real? Why would you do this to her, especially a woman?
Oh my god, I'm so stupid, I'm so sorry
I cannot find any reason why you would stub a cigarette on any person, especially on a woman's arm, as it could have really hurt her really bad and could end up with her having burnt skin that you are really at fault for. I suggest that you say sorry to her, and pay for medical bills that she may have and think about not doing that anymore to any other person in the future.
What was I thinking? I'm such a moron
I'm glad you are thinking rationally and realize you messed up. Let this be a lesson for you, so you will never put out a cigarette on her again. If you are angry next time, maybe just walk away and have some alone time so that it calms you down.