A female dog forced me to cum several times

So the title says it all.
It happened a few days ago. I was dogsitting the Dog of a friend. Its an so called "Appenzeller Sennenhund". I dont know why but i was always a little attracted to that Dog because of the tail moving upwards and basicly inviting to the pussy. She was in heat that Weekend and her pussy was swollen AS fuck. My Friend said He would BE Back in like 4 hours so i only took her out once and Then WE were sitting in the living room. And i watched her pussy. I couldnt resist to watch it. And she actually noticed. So i was staying in the room after going to the toilet when She stood up and came close with her ass to my balls and started to hump Backwards. I wasnt sure what was happening but I immedialy got a boner and turned Backwards too. Then she fall over, presenting me her pussy and giving me a sneaky look over her shoulder. I swear she was smiling and i was really turned on.i looked at the clock. Still two hours left and Then she started to get Up again pushing her back against me Again and fall over again. Giving ne that smile too. So that was it. I pulled down my pants and got on my knees. I was hesitating. Should i really do this? my Penis was just an Inch away from her entry but Then she crawled Backwards and my penis touched her vagina. That was the trigger. I Pushed it inside. Only to realize that it wasnt that easy. You see the Vagina of a dog is a little different. It has a 70 degree angle that you have to push through. But after a few pushes and adjustments i was hiting the angle and moved completly in....ngghhhhaaa i swear it was hot! Like really! The body Temperature of a dog is much Higher. And she was tight. I Just had pushed in and i was already going to cum. Then she growled and without a thought i started to thrust. But i didnt lasted Long. I was trying to hold it but her pussy was strong. You See a female dog has strong muscles down there and i was Feeling it and at the Moment my Penis twitched the first time her face turned around and her pussy was squeezing tight. I Watched her face and she mine while i was pumping a big load of cum inside her. It was so strange because i was trying to pull out but i couldnt. Thanks to the 70 degree angle and her tight grip it felt like i had to break my penis to get him out. Or at least swell down....but here is the thing after ten minutes i still wasnt able to swell down. Since i was Balls deep inside her, her Pussy was clinching on the end of the shaft were the vein is. So therefore she was like a cook ring Holding the bloodflow. Everytime i tryed to pull Out she came with me Backwards. I was actually a little scared to be caught like that but then her face turned around again and We watched our faces Again....a whole minute until i realized what she wanted... she wanted me to really fill her Up! She wasnt done and i had to deliver like a male Dog. Since i was still hard i started to thrust Again and she actually was loosing her grip a little so i could move better. So that was it. I probably was stucked to that dog until she would let me go. It was still to hot and to tight for me. I already came again just after a few trusts. The fuck didnt lasted a minute. But WE were not done yet either. She growled, tightened her grip again and i was forced to continue. I mean it was a hot and horny thing though. Forced to cum until the dog let go made me cum 7 times in just 35 minutes. Finally after the 7th time her grip actually got more loose And i immediatly pulled out. Not a single drop of cum was following. Her Pussy had taken IT all. She then licked herself, watched me again, smiled and Then WE were just going back on the Couch like nothing happened. When my friend came back the dog was acting normal and so i left with an empty ball sack and the dog with a full pussy. Would i do that again? Yes totally. Thats a completly different experience to having sex with a Girl. A more beastly one.