Too much focus on oral as if it's the only alternative to intercourse. Fingers can be just as good as the tongue for many things, for example. Not sure why using the tongue as opposed to fingers makes it worth a whole seperate study including socialbiological theory. Look, anybody who took care of somebody with tongue, fingers, caressing with hands, etc., is great. Anybody who left all those other things out, and did only oral and intercourse would be an incompetent lover generally, because there would be no foreplay, except for straight to oral.