1) adj. - taking a lot of money in bill form and tossing it up in the air. This is most effectively done at a strip club for the effect of raining one dollar bills on the dancers (and it makes them feel so pretty), or to snub a hater by throwing money into their face that then falls to the floor, like rain (use this when paying a debt to a punk bitch who keeps asking for their money to the point that they are ruining your friendship or when dumping someone who has been bankrolling you for a while now that you're making money).
2) adj. - the ability for a relatively small group or single person to move massive shipments of illegal drugs.
3) adj. - going on a scoring spree, such as a hot 3-point streak in basketball, or making a big shot that silences the opposition's fans.
"I'm in this business of terror, got a handful of stacks better grab an umbrella, I make it rain (I make it rain) I make it rain on them hoes."