Basically, it's synonymous to "Hit it and Quit it". Smash it and Cash It refers to having sex, (Smash It), and then bragging to all your friends, (Cash It).
It can also be used as: You have sex with a prostitute (Smash It) and then pay her (Cash It).
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the USCoast Guard in the area of Southern Florida.
"Base we've got some square groupers floating outside of Miami harbor."