You meet up with your date for dinner and everything seems normal. It's a lovely time, you share a few interests and the conversation flows easily, but you both finish your meals quickly. She takes you by the hand and leads you to a familiar part of the library, removed from the patrolling librarians and free of students.

"I had so much fun yesterday I thought I would prepare a special treat for you today" and with a grin she leans over a little further and shows off the neat little plug she's apparently had inside her all evening.

With a little gasp she pulls it out, letting it drop to the floor with a startling clamor and you realize it was heavy steel.
"I want you to fuck my ass, fill me to the brim, and keep going til every drop you have to give is spent, got that?"

You swallow, nod, and move to give her exactly what she asked.