nasal sex

A way of saying "I don't know", as in "fuck knows"

sexual intercourse with the penis into the nostril.
sexual intercourse with the nose into the vagina.

originally developed in neolithic times, nasal sex did not come into popularity until the recnet body modification craze whereas people were more inclined to enlarge various cavities of their bodies.
the penis is inserted into the nose, and thrusted until one's thick hot jizm spews onto the receiver's brains, known as getting some "hot brains". typically those of african, italian and/or jewish descent are popular within the nasally sexual set.

The act of sexual relations involving the nose

sticking your peepee in someone's nose

sex performed between a gnome and a normal human in which the gnomes penis is too small to fit in any of the regular sexual orafices, so is instead placed in the nose

To stick your finger up your nose and repeatidly doing motions to get a booger. In too hard motions, bleeing can occur.