Cochita refers to "Cosita= Thingy" or "Cosa = Thing". In Mexican slang it is used when someone is being adorable.
Ko: You're such a cutie, Andy.
Andy: Awww, cochita. You're the cute one!!
Cochita is the sweeter pronunciation of "cosita" which literally translates to "thingy". In Mexican slang it refers to someone being really adorable.
Ko: That's so nice of you, Andy. You're a cutie!
Andy: Aww, ¡cochita linda!