I don't mind if I do

(I) don't mind if I do

An affirmative response to an offer. A: "Would you like a cold drink of water?" B: "Thanks, I don't mind if I do." Ooh, free donuts? Don't mind if I do!
See also: if, mind
Farlex Dictionary of Idioms.

I don’t mind if I ˈdo

(spoken, informal) used to say politely that you would like something you have been offered: ‘Another glass of wine, Gary?’ ‘I don’t mind if I do.’
See also: if, mind
Farlex Partner Idioms Dictionary
See also:
  • (I) don't mind if I do
  • don't care if I do
  • (I) don't care if I do
  • don
  • don't get me wrong
  • don't beat a dead horse
  • all in (one's) head
  • come it
  • come it (with one)