I think it's because if you could taste your own tongue then it would be like you were french kissing yourself all of the time, and that would lead to feelings. You start to consider yourself more than just a friend and soon it's an all-out crush. But of course, yourself isn't interested in you because you've got a crush on some other you. You fall into a deep depression because you can't understand why you you're not good enough for you and yet you still keep coming back and making out with you. Finally you get so fed up that you get a gun and say something like "IF I CAN'T HAVE YOU, THEN NO I CAN!" and kill all three of you in a jealous rage. Then the cops would come and say "Yep, another double-homoside-triple-suicide-murder. What a waste." and they'd stand there shaking there head. So as you can see, not being able to taste your own tongue is a survival method produced by evolution. Now that you know, do you still want to taste your own tongue Tphrz? I didn't think so.
Because you're too busy tasting my tongue lulz
The question is... would you notice if you were tasting your own tongue. Because it's always in your mouth, you're used to its flavor... so there might just be one way to find out. You'll need to cut your tongue out, wait a little while... then put it in your mouth and see how it tastes.
You can you just need to bite down on it a bit harder.
