After Master leashed you for walkies, you remembered your dream from last night and practically dragged him out the door, hoping to find that park. It seemed like you had a lot of fun there with Master and that male... but... you weren't into males... were you? You are a male, yourself, and last you checked, neither Gay nor Bi.
Actually, you were Asexual and thus not really into anyone in regards to romance. But you distinctly remember being Male... and... Human? But if you were human why would you not walk like them? And why would you go around without their weird removable fur?
As all these thoughts ran around your head, you instincively walked over to a tree and crouched as you began to relieve yourself. Out of the corner of your eye you caught sight of Master standing there, waiting for you to finish.
'Wait...' you thought to yourself, 'Master! Master knows a lot. Maybe I should ask Mast...'
Then it hit you like a truck. The collar. The dog bed. Playing fetch with Mast-Jack! Not Master Jack! You looked at Mas-Jack! You looked at JACK about to try to talk with him once more and figure out what's going on... then you noticed all the people. You were in a park... naked... in front of others!
But before you had a chance to try and cover up, you began to feel a hot, pricking sensation all over. As you continued to you looked down at your forepaws... no hands? Whatever they were now, you looked at them and you saw tiny pricks of hair sprouting from them getting thicker and more numerous by the second.
You were growing fur! It was around this time when Jack noticed you were finished and began to tug you towards a fenced in area that looked... familiar somehow? But from where... this line of thought distracted you until you realized Jack had already led you into the fenced in area and unclipped the leash from your collar.
Your dream! You realized, astonishingly. The park looked almost exactly like the one from your dream the night before, though thankfully the Male dog was nowhere to be seen. However, this also brought to mind why you dreamed of such things. Most of it could be explained by the fact that you were becoming more and more canine. But you weren't female. You were male.
"Sammy! Here girl!" Master whistled from a bit away, "I found some toys for you to play with!"
As soon as Master called you, you instantly forgot what you were thinking about. After all, Master is more important. Though it did seem a bit odd he referred to you as female, the fact that Master threw a weird flat circle thingie towards you distracted you once more. You jumped and caught it in your mouth before proudly returning it to Master, tail wagging.
You began to playing with Master at the park. First you play with the weird circle thing, then with a fuzzy green ball. Obviously, Master has brought you here to play and run and have fun. Running about, you begin to bark really loudly. To your surprise, Master doesn't scold you like he did last night. In fact, you even see him bearing his teeth in the way humans do to express joy or pleasure. This makes you very happy for some reason, because you feel like something you had done caused Master's joy.
As you play with Master, every once in awhile you stop and squat down next to a tree or bush to relieve yourself while something, a voice in your mind and in the dream, tells you that it is wrong and you shouldn't be doing that.
But you don't care and ignore it as you continuing and barking, content to spend the day playing with Master. Suddenly, another dog enters the picture and judging by the smell, it is a male. It looks like the dog from your dream if only a bit different. Regardless you decide to play with him as well, after all, Master seems to be getting pretty tired. Plus he seems to be communicating with another human... a female according to her scent and the Mistress of my new playmate.
After observing the newcomers, I ran toward the male and bark out hoping for a response. As he barks back you feel different, a little hot, but you think it's a good thing. And dismiss it as joy from finding a new playmate.
The male gives chase and you run from him, letting him catch up occasionally, before taking off once more barking. When you do finally let him catch you, you start to play, growling and yipping gently. Then something inside of you begins to feel strange... warm, no hot. Excessively,, unbearably hot! And it's all focused on your crotch. You now realize why Master has been referring to you as female. The collar wasn't just making you a dog... it was making you a bitch!
You instinctively lift your tail, faceing away from the male as you lower yourself submissively. You can't help it though and as the male mounts you, something in your mind tells you this is wrong, but you don't care as the male dog slides his rocket into your virgin hole. And that something goes away as your mind explodes in ecstacy. You can vaguely hear master chuckle before saying, "I didn't realize Sammy was in heat."