what is tok kong?
It refer to a fighting spider that fight with one big front leg
(kong) for a female. This term is restricted to the usage in Sg or
Malaysia.
so I'm not horny.

You are really tok kong! That is a very good etymology
from you! You see, the dictionary does not provide hints to
it's formation, it's states it's current form that's all:

(boxed up in red)