Hmmm, cockwarming isn't really a thing I'm into but I have the strong feeling that Zoro likes it a lot. I think he'd like to just keep his inside Sanji as long as possible and only really pulls out when Sanji gets annoyed at him. Sanji probably doesn't mind it too much but I think he'd hit his limit after a while cause it'd get uncomfortable - Zoro's a big guy after all XD