In my late teens (we start driving at 17 in Australia) I used to sleep over at a girlfriends house after date nights because the trip home was about an hour and the very relaxed parents preferred us to sex at home as long as precautions were taken (they took her to the doc and put her on the pill). Caz's bedroom was a converted basement that also had an outside door, and the family had no problems with her and I doing what all young people do when in love. So the pattern was that we'd go out for dinner/fun, get home at whenever, let ourselves in by the bedroom door and have deep delicious sex. She'd fall asleep and I'd go up the internal stairs to a spare room and kip until morning.
The family pet - Sam - was a large rangy dane-labrador cross, who had the run of the place and had inherited the best of both breeds. One night, probably about a month since Caz and I started all this, I was heading back to the spare room - smelling of sex - and Sam keenly followed me, clearly drunk with the smell of leftovers.
By this time I had been getting knotted for about a year (my first was a school teacher's boxer that I used to walk for pocket money but he got much more than a walk and I much more than pocket money and I discovered dog walking had more benefits than money and exercise). So I knew full well where this could lead!
Quickly into the spare room, door closed, clothes off, and instant tongue bath. Being a labradane, Sam was very tall and very solid. He'd already established a reputation for pillow humping and furious dick licking so I knew he would be horny. I was swept away by the tongue bath. I sat on the edge of the bed and let him go to town on my dick and I reckon he was fantasizing about Caz and expanding the relationship. He moved lower to the balls and was clearly following a scent trail, so I lay back with legs in the air and for the first time got a deep rimming from a dog. Another first that had me hooked for life. There is nothing like a deep rimming from a dog with a long forceful tongue. It also beautifully opens up the arse. I had never been rimmed before, it was a new experience but being pretty analcentric my dick sprang to life and I went from mildly aroused to super horny and desperately wanting something deep inside.
Don't know how long he was there, but I could feel that tongue taking a deep exploration and it was hard to stop the urge to grab my rock hard dick and thrash away for a quick orgasm. But I was hoping for much more than this and so eventually flipped off the bed, assumed the position and he needed no encouragement. He leapt on my back, grabbed my waist and his dick was frantically looking for somewhere to go ... you know what it's like - that sharp initial bony point going bam! bam! bam! bam! bam! seeking a hole lot of enjoyment. To all knowledge Sam - aged around four - had not yet penetrated anything but lots of pillows. So often the case for family pets. No wonder some of them get antsy. Anyway .. back to the action.
I reached back, lined him up and with a deep grunty bark, he was in and suddenly about four years of pent up sexual need found an outlet. Fast, furious and forceful. Sometimes they don't really know what to do. Sam definitely did and my whole body shuddered under the force of this 40 kilo dog's frantic first furious fuck.
He hammered and hammered and hammered away - a rough, primal pistoning as his deeply repressed but insistent instinct took over and Sam only had one thought - his dick was deep inside something warm and moist and fuck this feels good!! The knot started to grow and he gave my ring a solid pummel - more and more pleasure as the knot expanded. As the resistence grew, the harder Sam thrust. The more the knot grew the faster and harder he thrust until with a last foreful "plop" what I later discovered (yes of course there were repeats) to be a huge knot (easily the size of a large orange) was ruthlessy forced in and could not come out any more. But he kept hammering that long dick and massive knot deep inside, clearly swept away in fuckland with no regard to what was underneath him apart from the pleasure it gave him. My insides were pummeled into submission. I felt the warmth of his presence deep inside and it all becoming slippery and slurpy as he started to squirt himself into me. Then it started to push against what I now know as my "second ring". I had felt his dick expand into it, but the knot was now being pushed to its extremity. (Sam remains one of my dick size record holders). He felt it too and thrust even harder until I felt a sharp stabbing pain as the knot slipped past and was now very deeply secure. At this time I had not learnt about fisting (that followed two years later) so everything was nice and (relatively) tight.
Of course he then tried to turn, but I had learnt about this the hard way. Nothing worse than the knot being pulled out in the turn and not only the pain of a full withdrawal but also being deprived of that deep throbbing pleasure that only a fully inserted pumping dod dick can give. So I grabbed his front legs, pulled them over my shoulders and felt him throb and being the long unload. He drooled all over my back and kept gently humping as he pumped, dumped and drained himself into my joyous arse. He was deep, large, hard, meaty and throbbing and I felt him pumping and pumping and bumping my by now swollen prostate. His knot had been milking it for ages by now and there was a good sized pool on the wooden floor. I had a wondrous hands free orgasm and a series of internal orgasms that shook me hard.
Eventually his knot began to shrink and it slipped past the second ring and eventually with a little whine he slipped out, gave my arse another deep licking session and he lay down to lick clean. I stood up and had found the tissue box, wiped myself (and the floor) clean, sat on the bed, tuned out the light and my mind was revelling in the primal pummeling and already thinking about how Sam would do this again in the future ....
Then the door clicked, slowly opened and my girlfriend shyly peeked around it into the dark room. "I'm still horny ... I can't sleep ... come back downstairs - Oh! Sam's here. Is he annoying you? I wish he wouldn't keep licking his dick like that ...
