>What programs do you use for making this?
3D studio to plan the animation and create a reference, then I draw and color it in photoshop.

>And how much time can it take
A long time. Too long, really. I've never timed it exactly, I usually spread it out over several weeks.

I like to see conquest, girls being ravished with a dominance/submission angle. I imagine she is taken roughly. It is pleasurable but she is still alarmed at his ferocity. She climaxes and is still along for the ride until he finishes with her. As he pulls her hips close and cums deep inside she is conflicted between physical pleasure and fear of pregnancy. Maybe even a twinge of humiliation that she gave into her submissive instincts so easily.

It's insemination as a form of dominance. It's a little fucked up but there you have it.