Define 63 Meaning

A sexual position similar to 69. In 63, the girl is on top, and instead of giving the guy head while he eats her out, she lets him titty fuck her. The outline of her boobs is like the number 3.

A slang way of saying down syndrome, usually used to insult someone. Derived from the fact that down syndrome is caused by 3, 21 chromosomes.
(3*21=63).

Refers to a tricked out (luxury) 63 chevy impala from the west coast with nice hydraulics.

When you get a little bit of this, with a little bit of that.

having sex in the ear

A tricker position than 69.

The guy is standing up while he’s inserted into the girl who is reverse cowgirling and bends her body forward to eat out his ass.

(Internet slang, fandom slang, informal) The proposition that it is possible to find genderswapped versions of every fictional character, especially as fan arts on the internet.

Rule 63 is a rule of the internet that reads as follows: "For any given male character, there is a female version of that character." This rule's exceptions are only in the instance that A: the male character is already so androgynous that a female version would be basically the same, or B: the female version hasn't been drawn yet.

What Madison Martin thinks there is

A 5.56mm general purpose machine gun system. It could be fed from a large capacity magazine or belt, and was a modular system capable of serving in the assault rifle role. The most prominent use of the Stoner 63(A) was by the U.S. Navy SEALs.