Q. Why is French kissing allowed, and saliva swapping allowed, but not all types of blood and other swapping?

A. Saliva is pure (paak). Fluids from the urinary track area as well as the stool area are impure. So is blood when out of the body and upon one’s clothes, etc. Coming in contact with such fluids makes the area of contact impure. Therefore, all types of fluid swapping other than saliva, while taking part in shared intimacy, are not allowed in Islam.  (Simple, no?)

(Your question was distastefully phrased, so we had to edit it for our normal Islamic audience. What would grandma say to your original question and its link to manners?! Nevertheless, do not take it persoanly; we are glad to help you and your Halal partner)

Allah certainly knows best.