Hello doctor, what is the risk of genital rubbing (penis to penis, precum presented)? how about rubbing a penis over the anus (inside part of anus, no penetration)?

Follow the math...: If a guy folds his penis over and rubs the penis front back on itself, there's no risk with his one penis. If 2 penises get involved, that means 2 anuses too. If a third penis and anus get involved, even if at a different time, that's a much bigger risk. Combinations then are: P1+P2, P2+P3, P3+P1, P1+A2, P1+A3, P2+A1, P2+A3, P3+A1, P3+A2. Watch out for Herpes, HPV, Syphilis, Gonorrhea, Chlamydia.