"Cool cool." Many uses, all of them
(a) In L33T speak, "cool cool" is used as acknowledgement for absolute understanding, no further discussion on the matter is necessary, as in "So we're not going to play beer
pong? Cool cool. Let's do keg stands."
(b) Kk also
means, "cool cool", also
means "ok, cool'
(c) "cool cool" also
means "I get it, and that's cool."