I've known people into that stuff who seemed to like to broadcast information about it. This is about them, not me or you. Of course, it's somewhat of an invitation into the subject. I'm not interested in it, as seemingly neither are you. Josie had good advice. Mine: tell him you don't want to talk about this, or for him to contact you. If that's what you want. Yes, sometimes people get bruises from enjoyable activities (eg outdoor activities) and they even brag about it. However, I think that's kinda stupid and even stupider in a sexual context, so I would avoid the person for sure. If a guy I barely know is contacting me frequently, that's a giant red flag. You may feel differently.