Lisa toys with her ass

Lisa let her pet sit there for a few minutes while she got ready. Before she went into the kitchen, she barked to her sister. "Close your eyes! I want this to be a suprise." She peeked around the corner and saw that her sister's eyes were shut tight.

As Rachel was approaching, she heard the clacking of boots against the floor. She didn't try to move. She simply waited for her mistress. "You're such a good pet now, aren't you bitch?" came her voice.

"Arf!"

"Good. Then you'll enjoy what I have in store for you." Rachel felt hands grab her ass and spread her cheeks. Then she felt something poking at her anus. 'Oh god.' she thought.... 'she's going to fuck me.... in the ass!'

Lisa sat on her knees behind her sister, slowly pushing the intentionally unlubricated strap-on she was wearing at her sister's ass. She pushed and pushed until, at last, the head popped into her sister's arse, causing her to cry out in pain.

"OOOHHHHHH GOD! AAAAHHH!" She cried, only to be smacked on her ass several times.

"Shut up, bitch!" Lisa yelled. "Express your gratitude!" She pushed the strap-on deeper and deeper into her sister, until it's full seven and a half inches were inside her.

Tears running from her eyes, Rachel could only weakly bark as the pain overwhelmed her. Lisa reached up and drove he face to the ground, rasing her ass. She then began to slide in and out of her sister's ass, and soon, the pain began to mix with pleasure, but Rachel was still in tears. Lisa only increased her pace.