Bri waited until her parents had gone down the driveway and drove out of sight before running back upstairs. They were going to Vermont for their anniversary, and she had the house to herself for the weekend. She was eager for time alone so she could experiment without getting interrupted. At fourteen, Bri was just discovering masturbation. She had had no idea it existed until reading about it on a sex site. Bri's mom was too uptight and prudeish to talk to her daughter about the birds and the bees, so finally she had taken sex education into her own hands. So far, Bri mused, she had learned that you called your vagina a pussy, and the little feel good button at the top was called a clit. Once in her room she hastily undressed and layed down on her bed. Buster, her bulldog, looked up at her from his spot on the rug. He wuffed softly. Bri ignored him and spread her legs wide. She stuck her finger in her mouth, wanting to get it wet. This, she had learned, was called lubrication. Once ready she started to gently rub the tiny nubbin of flesh. She jerked at the wet friction and moaned a little at the pleasure. She rubbed slowly at first, using her other hand to tease her nipples, then sped up when she felt she had the hang of it. She felt herself come to the edge of an orgasm, but the feeling went away as soon as it had started. "Christ!" she muttered, and sat up on her bed. "I almost had it," she said to Buster. He got up from his rug, walked over, and got a whiff of her dripping pussy. Immediately his nose and tongue were all over her tiny cunt, licking furiously. Bri's attempts to push him off were soon forsaken as pleasure overswept her. She fell back on her bed and started thrusting her hips at Buster's snout, moaning and panting. His huge tongue swept her pussy over and over, the tip touching her clit each time. It took her less than a minute to come, and she lay on the bed, breathing harshly. Buster looked a little out of breath himself, and when Bri finally sat up to pet him in thanks, she noticed that his doggie penis was starting to harden and come out of its sheath. Upon seeing her bulldog's cock, Bri had an idea. Her dog had been her best friend for the last eight years, so who could be better to lose her virginity to? Bri knew it was wrong, but she also knew she was as horny as hell, and right now that feeling drove all moral things out of her head. Bri scrambled off the bed and started pulling her blankets to the ground. She spread them, then called Buster over. He came willingly enough, smiling a doggie grin at Bri. His penis swayed back and forth when he walked. When he stood by her she reached out one small hand and stroked his length. She gasped. How could something be so hard and soft at the same time? Buster whined eagerly and started to hump his mistresses hand. Bri knew the next step had come. She got on all fours with her butt and pussy pointed toward Buster. Having done this on dogs before, Buster immediately jumped on her back and started thrusting. In a minute he found the right hole and slammed his six inches in. Bri's hymen broke with a pop and she screamed in pain. Buster took no notice and kept humping her pussy with all his might. In a few minutes the pain reduced and Bri began to moan and thrust back against Buster's cock. "Oh God Oh God Oh God," she chanted as Buster's cock brushed her g spot and his furry balls slapped her clit. She started coming and the orgasm just kept going, renewing itself with every thrust. Suddenly a new type of pain began to surface as Buster's cock grew a knot. He slowed, then pounded deep into her with one hard thrust. His seed streamed into her pussy, and the knot grew to about the size of a tennis ball. Bri was crying, she had never felt something so good and so painful at the same time in her life. Buster lay over her panting, and his weight caused her to collapse on the floor. He landed on top of her and his knot drove in another inch. Suddenly Bri was coming again, spasming against the floor and moaning loudly. When coherent thought entered her mind again, she realized that the knot had shrunk and Buster had pulled out of her aching pussy. Her once tiny hole was stretched wide and dripping a mixture of blood and dog cum. She lay on the floor thinking that she would have Buster pop her anal cherry tomorrow.