Today, I have safe sex (use condom) with a CSW. Everything seemed fine. Except that I remember that when both of us were naked, she sat in front of me (sat on my stochmach) (to require me to take pics of her) and her vagina touch my penis. My penis at that time was soft and I didn't not feel anything (like being excited or feel my penis inside her vagina. I'm pretty sure I haven't penetrated her at that time because I really didn't not feel anthing like being excited or my penis inside her. But when at home, I rethink that and I'm really worried I may penetrate her without knowing. I also ask her and she said that the penetration didn't happen. I'm afraid she tell lies or she also may not know/feel it when penetration occurred. So please may I ask that am I at risk and should use PEP for this incident. Thank you for your time