Lucy's thoughts might be confused, but her libido was not. Lucy just barely had to tap on her too taut skirt near her belly for the pressure to send her skirt flying up in one direction and her canine cock erecting out from under in the other direction. She spun her sister Jeff's computer chair around to face the backside of her mother who was on all fours and found it was only a slight adjustment to the chair height to have her dick at just the right spot to guide it into her mother's dripping snatch.
Once lined up, Lucy took a second to appreciate the view. She admired her mother's backside, the way her hair fell down her neck, and the way she seemed almost surprisingly and obediently comfortable in doggy style position. She recalled the way her mother had sexily bit her lip at her and the way she had whispered her pleas to be knotted by what she knew to be the house's most superior cock (despite Lucy only having had it for a minutes before her mother came in to her sister's bedroom, from her perspective). Thinking of those pleas, Lucy found a surprisingly dominant tone unlock as she teasingly brushed the lips of her mother's quivering pussy, "Is this what you want? Are you sure?"
"Please!" Lucy's mother's attempt to keep her enthusiasm quiet sounded a lot like the whine of a dog begging to Lucy and that was exactly what she wanted to hear.
Lucy gently slapped each cheek of her mother's butt and then roughly grabbed her mother's hips and pulled the two of them together. Lucy's aim was perfect and her mother was incredibly well lubricated and as rough as Lucy had tried to make the maneuver seem, Lucy thought it was a surprisingly smooth coupling maneuver. Lucy removed her arms from her mother's sides and instead moved her legs around to squeeze those sides. (She tried to keep most of her weight on the chair however, as she didn't need to give her mother back problems.)
Lucy could feel the swelling that let her know that she and her mother were locked in now for the duration. It took only a little bit of grinding to verify that she had knotted her mother quite strongly and they weren't going to leave this position until Lucy's pecker was soft enough to let them.
Lucy glanced at her hands and then down at her mother's dress covered dangling boobs just a bit out of reach of her arm length and then selfishly down to her own boobs. Her hands landed there, making a wrinkled mess of her blouse and doing their best to tease as much of her nipples as they could through the bra she hadn't thought to remove before getting started pounding her mother. One of her hands decided to seek the long journey towards hopefully better luck below. It did have some difficulty making it through the tight maze between her thighs, down the slope of her mother's butt very tightly against them, around the girth of her cock and then finally below her panty to the wet glistening prize hidden below her cock. She growled with dominant joy as she was able to tease her soaking cunt and her clit with her fingers. Lucy couldn't be sure if her mother was getting everything she wanted out of this pairing, though her mother's stifled moans which still seemed surprisingly dog-like in the moment seemed pretty favorable on that score, but Lucy was having the best sex she could imagine. Even with the weird repercussions to her home life, or perhaps especially because of the weird repercussions to her home life, Lucy was in both dog-stud and human-girl heaven with a tight bitch clamped around her knotty canine cock and hands to masturbate and tease her nipples and human vagina.
It was, of course, that moment of Lucy's bliss that her father swung open her sister Jeff's bedroom door to let Jeff back into her own bedroom. Given Jeff didn't really have hands to manipulate doors in her doggy form, she seemed quite grateful for the assist. Their father seemed much less pleased to discover his daughter deeply knotted into his wife."I can't believe you!" Lucy's father shouted at top volume. Lucy couldn't tell if he was on the verge of tears or angry enough to hit something or someone. Before Lucy could get a sense of the emotion, and maybe because she was very clearly mid-multiple orgasm and couldn't think straight if she tried, Lucy's father huffed back out of the room. Jeff hopped up onto her bed and laid down in a very doggy way that made it clear that she was watching everything about Lucy and their mother and the way they were locked together and the fact that they had few choices but to resume their briefly interrupted humping.