Unlike the original saying "Take it with a grain of salt", this term is used when you tell someone something heavy or harsh, but you want them to take it as nicely and sweetly as possible (which is where the sugar part comes in).
"Take it with a grain of sugar, but you look like you just rolled out of a grave"
"Take it with a grain of sugar, but your soufflé is terrible"
When you have a sand timer for something and at the very end you slam on the top so 0.00036% more sand comes out for the next millisecond. Eventually adds up to about 4.5 seconds out of your life that you didn't spend.
My little brother was brushing his teeth and when he looked away I slammed the pussy's time so when he tells anyone he brushes for 2 minutes I can correct him 'cause of The Lost Grain.