How bad is this for the other person?

Im a good looking girl with a huge problem. I totally act like a boy! I actually think its fun and funny to hold down guys who are smaller than me and fart on their face. Everyone laughs when I do this and I get reinforced. Even the people I fart on laugh. However my sister who is my polar opposite says this is very distateful and disrespectful to the person I'm "breaking wind" on as she would call it. Is there anything wrong with farting on someones face to be funny?