Stands for "big name fan", as known on tumblr. Within a fandom, there are usually multiple people who are known fandom-wide and who have many more followers than other people. These people are known as "BNF"s.
Evarren was a BNF from klaine fandom before she deleted her blog.
having sex with a girl in a wheel chair then pushing her down a hill or stairs
man I just did cindy the cripple, when I was done I pushed her off the roof though because she was a bitch...twisted metal baby