X on top is a term used when saying that you are not interested in anything else than a physical relationship and that you would not grow attracted to anyone giving you that.
The uses include but are not limited to:
1 a Greating
2 a Personal Message
3 a Good Bye
4 a Random Phrase
Example :
Hey Stacey X on top.

Now X on top.

Ok see you later Stacey X on top.

In the club he just kept saying X on top and some girl took him to the bathroom.
by JamalSlide January 7, 2018