Sometimes it can be used as slang for the word "love" as well, since in Japanese, "daisuki" means "to like a lot."
So, If you "daisuki" something that means you like it a lot.
Japan has a lot of slang for their phrases (as do most languages), so people who slang their words, or who don't like long sentences/words don't bother to say "daisuki" would just say "suki."
Also, "suki suki" almost seems like the "cute way" to say you like something!
AND, it is NOT a blowjob; spell it RIGHT - it's SUCKY SUCKY, not SUKI SUKI. Please see Sucky! Sucky! Five Dolla! for the right reference!!!
Your answer can be a "suki", meaning "Yes, I do!".
Or "karaoke, suki?" meaning "Do you like karaoke?"
Boyfriend: What do you say to a nice home-made dinner and movie by the fireplace?
Girlfriend: Suki suki!~ ♡