Sending explicit pictures without the recipient's consent is a clear violation of their personal boundaries. Consent is fundamental in any form of communication, especially in intimate matters.
Flirting, as with any romantic or sexual interaction, must be consensual. Persisting in flirting after someone has clearly stated their sexual orientation is a violation of consent.
Many women find it frustrating when men don't grasp the simple concept that they do not want to be touched with unwashed or dirty hand