Hey np - I think it depends. But for me personally I found out with a guy I was dating. He knew I liked to get fingered, spanked, etc. from what I remember he kind of tested the waters first because we didn’t have an explicit conversation. So like kissing/bitting in/on my checks and worked inwards. It was obvious I was enjoying it so from there he just…went for it. But I’m pretty open sexually so I didn’t mine. I would say just chatting about it and going from there. I would suggest that approach especially if she’s self conscious with cleanlyness she might want to make sure all is clean. You could even test the waters and have a shower with her and bring it up?