When a woman giving a blowjob uses her teeth in unpleasurable ways.

Someone who is so totally completely pan-handled that their friends would be able to place a punctured inflatable shark toy on their head with little resistance and proceed to chant "He's got a shark on his head, shaaark on his heeadd!" if they so pleased.

When a girl bites your dick or scrapes your shaft with her teeth during oral sex. Typically drawing blood or ruining the entire Bj in the process. A girl that has tendencies of treating your dick like a Oscar Meyer selects premium angus beef hotdog and snapping into it with her sharp fangs. Essentially like shoving your cock in a sharks mouth.