An ex-girlfriend of mine always wanted me to creampie her while she was on her period. It's a lot harder to get pregnant at that time (though not impossible so exercise EXTREME CAUTION) and she said her hormones would rage during her time of the month so it just made sex way more intense for her! What was so exciting to me was the sense of danger! She would always look into my eyes and tell me to do it and I would ask if she was sure but that was part of the play-acting you sometimes do in bed. I would let it go inside and it was always magical! Never got her pregnant and she would cum every time!
Then my very next girlfriend always wanted me to pull out and cum in her mouth! Same kinda thing for her, she liked the "forbidden" or "dirty girl" aspect of not only swallowing my cum but sucking on a cock wet with her own pussy juice (She liked the taste of her own pussy on my dick...she told me this!). She had a nice soft petite body (I'm a tall guy, medium to muscular build. She was Japanese and very small.) so with her there were times I wanted to blow it on her tits or even her stomach and just watch it drip down her ribs or her waist as I came down from my orgasm. That was exciting for me! Seeing my work! She understood where I was coming from (no pun intended) but she got off the most when she knew I was gonna finish at the back of her throat! I'm sure she's somewhere making some other guy VERY happy!
-Nasu