As unnecessary and inappropriate as you find cold calls from salespeople, women tend to find "dick pics" just as inconvenient. If you've never slept with her and you decide to send her a picture of your penis that she didn't ask for, you look creepy as hell. Stop it. And, if you have slept with her and have a great relationship, she already knows what your dick looks like. What she doesn't know is how to explain why she received that picture at lunchtime to the co-worker looking over her shoulder. You may think you're turning her on, but honestly, guys, it's not.