Sexual harassment is based on how the target perceives the harasser. If she's attracted to him, it's just "playing around".
But most chicks are attracted to guys who don't overtly make sexual jokes. Actually, a girl will respond better to indifference toward her existence -- but that all hinges on whether or not she's attracted to you. If you don't know when a girl is attracted to you, then you definitely shouldn't be trying to joke around sexually with her.
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