It was apparently to wet his fingers by using her spit as a lube? I don't know, but it seems a very weird thing to do to someone you just met (Or.. at all. I don't find that sexy.)

And I do agree - it should be common sense! And many men do practice these things, but I've also met some who just seem clueless. My favorite experiences have always been with men who made sure to ask me questions and communicate with me.