In #MuchCoolerDai's Dai Savings Rate contract (Pot), drip is the function that updates the DSR accumulator (chi) and adds Dai by calculating the system debt (vice) of Maker Protocol's balance sheet (vow). Drip has to be called when a user adds (join) or withdraws (exit) Dai from the DSR but anyone can call it any time!
To learn more about the tech behind DSR, Dai and the rest of the Maker protocol, check out the docs at docs.makerdao.com.
There's Dai in the Pie right now earning % a year.
A technical PSA by @adrianleb about the wonders of DSR, View Source