Olivia shows promise, Mia not so much

You start by explaining them the basics of magic. It’s how you started teaching Doe so it should work for them too. But then Olivia and Mia interrupt you and explain the basics right back at you.
“Doe has already told us about this yesterday.” Olivia explains. “But she hasn’t thought us any spells yet.”
“Yeah, show us how to cast spells.” Mia continues.
So you teach the two a few basic spells and tell them to start practicing. While the foxgirls try out their magic your thoughts drift away. You focus on the issue of the tails the foxpeople have.

You mull over several possibilities but don’t get any closer. In sheer frustration you decide to take a step back and start at the very beginning.
First there is Doe who had no magical abilities and after transformation started off with two tails as well as an interest in magic.
Then there was that kid you transformed in the capital. He too didn’t seem to have any magical abilities and got two tails as well.
The cousin-loving sorceress was a court mage for a low ranking countess. Due to her young age and the sorceress’s low standing you can guess she was a novice in magic. Powerful nobles tend to hire older, more powerful magic wielders. That one started off with three tails.
Next was this merchants whose mistress you transformed. She had no magical abilities either, like Doe. Only she had just one tail instead of two.
James, Alice, Lisa and Shirley all have three tails. As battle mages, they only ever trained in using small spells to augment their martial skills. Though they are quite skilled in the few spells they know. Enough to get an edge on their opponent.
Due to his age Robert both has better martial skills as well as more expertise in magic. He is also the only lieutenant with four tails.
When putting everything in perspective like this, you suddenly seem to notice that the higher the magical abilities of the person, the more tails they have. In fact, every time Doe showed greater skill in magic, it was quickly followed by a new tail. If that’s true then …

“John?” You hear Olivia say.
With your thoughts disturbed you look up and say “Huh?”
At first you see Olivia’s cleavage. Then you look further up to meet Olivia’s face. She has quit her practicing and is standing close to you.
“Is something bothering you?” The dark haired foxgirl asks.
“No, it’s fine. I was just lost in thought.” You say. “How is practice?”
“For me it’s fine.” Olivia says. “I managed to try out all the spells you showed. But Mia seems to be having difficulty.”
Both of you turn your heads to Mia. The single tailed foxgirl is holding her hands in front of her and concentrating really really hard. So much to that her face started turning red.
If your previous thoughts are correct, two tails show an untapped potential. Three tails is apprentice level and four tails are adept. One tail however, might telegraph no latent magical abilities. Suddenly you wonder just how many tails you would have if you got turned into a fox.
“Goh, forget it.” Mia frustratingly says. “It’s not like I care if I have magic … I’m hungry. I’ll go get something to eat.”
“Not too much, sweetie.” Olivia calls at her friend. “You wouldn’t want to go back to being chubby again.”
Mia opens the door, look angrily at Olivia and yells “Screw you!” Before slamming the door behind her.
Olivia giggles and turns back to you saying, “Well, just us two now.”
Your eyes quickly dart to Olivia’s boobs then back to her face.
“Yeah, just us.”

“Do you like them?” Olivia asks.
“Like who?” You ask a bit confused.
Olivia points with her index fingers at her boobs and says, “These two.”
“I euhm …”
“It’s fine if you do. I was working as a **** at a whorehouse before your lieutenant came and rescued me.” Olivia explained. “Guys staring at my boobs was normal there. I quickly got used to it.”
“Yeah well. The low cut certainly draws attention to them.” You say as your eyes go back to staring at Olivia’s cleavage.
Olivia smiles and asks, “Wanna see them?”.
You raise your eyebrows in surprise and look Olivia in the eyes.
“I don’t mind if you do. Like I said, I’ve gotten used to guys staring at them.” Olivia says while she grabs the shirt. “Besides, I’m feeling kinda hot. Probably because of casting all those spells.”
Olivia then pulls the shirt up, letting her boobs bounce freely in front of you. You can see she’s been sweating. She then drops her shirt on a table nearby and then the foxgirl stretches her arms above her head.
“Mmmmhh, what do you think?” She asks.
“They are quite alluring.” You admit while staring at them.
“Thank you.” Olivia says with a smile. “If you need to jack off to them, feel free to go ahead.”
Then Olivia goes back to casting her training spells.