"lets see that back side of yours, with a good bit of tail to boot, my wolfie friend" Sam said as you turned yourself over, your ass in your friend's direction as you focused your transformation on your backside and, to some degree, your spine.
You control your breathing as your tailbone grows out, breaking the skin, and forming a small flashy numb at the base of your spine. once you have a point of exit for your spine, you focus on growing it out, trying to maintain your breathing as you feel your Spain pulled down your back and hear the vertebrae pop, crack, and reform as the tail from a thick, hairless lump of flesh to something a bit hairier. Thick brown hairs sprouted from the tail as it grew out about 26 inches as the limb started to move from side to side, waging as the muscles and nerve endings link up the limb to your brain.
You feel some changes bleed to your backside as your anus has grown larger and darker and your ass cheeks thicken with muscles. brown fur growing over your new cheeks as you feel your tail start to rise up into the air suggestively. Your body naturally produces a lot of pain-reduction hormones. While they do what they say, they also lead to a rush of pleasure and arousal.
"boy, you're getting thick there, and that tail is being a bit suggestive there." Sam saids jokingly as you look to see your tail stray up in the air like its inviting someone to mount your wolfen backside. feeling your penis starting to swell up with blood as it starts to harden.
"The changes this slow can be very...arousing, a way the body encourages me to change faster," you reply as Sam ask you to take different suggestive poses of your backside and tail for his anatomy study. while you were posing, I was thinking about what to change next.