Evard’s Black Tentacles (wip)

"I would like to see you in my study, apprentice."
The words come at a shock to the young wizard but not an unwelcome one. She quickly closed her book and prepared herself to meet with her mistress, another session sounded heavenly and the mistress always managed to surprise her.
The small girl quickly scurried her way into her mistresses chambers. "Ah there you are my apprentice, come stand before me I wish to show you an example of a higher level spell for you." The apprentice couldn't help but spy that her mistress was concealing a bit of squid tentacle in her hand. Before she could process this information though the elder wizard was already speaking the verbal components to activate the spell. The apprentice let out a squeak of surprise as the slimy black tendrils quickly wrapped around her extremities. She was forced down to her knees until her lower half was flush with the floor.
"This is known as Evard's black tentacles. It binds the creature but it can have other... uses." The mistress drew up a seat in front of her pupil, making the hand signs that issue the commands to the tendrils. The apprentice let out a surprised "eep" as she began feeling her entrance being probed by one of the tentacles sprouting from the ground. Slowly they pushed and prodded and pushed aside the clothing barriers until it reached her unguarded entrance. The mistress gave a small smile as she gripped the chin of her trapped pupil, "Now you are going to pleasure me with that mouth of yours as I pleasure you the same."
The apprentice nodded eagerly and slid her face between her mistresses thighs burying herself between her folds eagerly as the elder wizard made a sign with her hand. The apprentice made a deep moan into her mistress as the ebony tendrils slid their way inside of her. It began thrusting deeply in and out of her slowly stretching her walls penetrating a bit further every time. Her arms were bound but her body was desperate to be touched. More tendrils sprouted from the ground to fulfill that very wish as her mistress gripped her head in pleasure.
The pace of both began to quicken as her body was caressed by the thick tendrils. She could feel her mistress' fingers in