From the very beginning, we notice a problem with all this reality business. Is ink "really" dripping from the speaker's mouth? Or is this just figurative language? A little bit later we learn that this is real, for the speaker anyway.
The librarian does not believe what she sees. (4)
By now we get that the speaker is really eating poetry. But even the librarian can't believe this version of reality. We understand that reality is largely dependent on the personal experiences on both sides.
When I get on my knees and lick her hand, she screams. (14-15)
Well, no big surprise there. It looks like the speaker is having a go at conveying his newfound reality to his librarian. The only problem is that she just doesn't understand any of it because she's not the one experiencing all that joyous poetry eating. So what's left to do? Why scream, of course.