What kind of book do you suppose she’s reading—fantasy? …sci-fi? …some sort of lewd instructional booklet*? …horror?
Insert your own suggestions in the comments, if you like.
FUN FACT: The picture was supposed to also have a bundle of rope beside the gag, but the artist couldn’t make it look quite right… …or maybe somepony off-panel stole it and is encroaching upon her from behind, explaining her shocked expression. *Who knows?*