Add me to the club..
Although dog-sperm and human-cells don't 'connect' or 'fuse', and thus you can't and won't get pregnant with a dog-human-hybrid or anything (something with chromosomes not matching etc. I never followed biology that much), the idea and feeling of being filled up is a turn on in itself.
There's a whole thread here somewhere with more technical mumbo-jumbo about how for a brief moment the dog-cells do 'attack' the egg - and thus, technically, you could be called 'impregnated' for a brief second - and i don't know if anyone else shares that thought, but even thàt turns me on! Dogs (especially if you have a big one
) already shoves you around and dominates you when he's on top, even more if you are pinned or tied, his knot doing it's job to stay locked inside you and fill you up as best he can... and then to know even on a microscopical level his cells boss yours around...!!! ?
i dunno - maybe i'm a nerd about it... ? lol
And of course the whole aftermath is hot too: dog cum leaking out and making a mess, feeling lips bend and stretch as he pulls out... looking at his dangling knot realising "holysh*t i just had that in me!" ?