I suppose the origin of the saying was in connection with some kind of drink, but noways it can also be used as some kind of toast when somebody says something you completely agree with.
I’ll Drink To That: Politics as Pop Culture
Tasting the Web: I’ll Drink to That!
this is the normal context:
drink to sth phrasal verb
If two or more people drink to something or someone, they hold their glasses up at the same time and then drink from them as a celebration, or to show respect or good wishes:"Here's to a prosperous future then." "I'll drink to that!"
What should we drink to?
It is common to drink "to something," in order to celebrate or honor it.
Ah, you also might want to follow this piece of advice:
jejejeIf some Russian asks you nicely do drink to something, do not try to follow them. You will crawl away and die not even half way through while the Russians are happily downing their 20th toast of the evening....