Although they don't hurt, your arm and leg do feel a little cold. You get your laptop and sit by the window. The feel of the sun on your scales is wonderful. You search the internet for photos of rattlesnakes, looking for something similar to what bit you or to the markings on your new scales. They are closest to an Eastern Diamondback, but not the same.
You feel your nipples get hard. Looking down you can see the scales are beginning to spread onto your right breast. While the scales on your arm and leg have been fairly consistent shades of brown, some of the scales on your breast are forming darker lines, like a bullseye target with your nipple in the center. It reminds you of the tail of some rattlesnakes leading to the rattle. Your right breast stiffens and swells as scales encase it. At least you'll never need to wear a bra again. You fondle your transforming breast and it feels good.
You realize you're getting turned on and want to masturbate. You go to your bedroom and get your favorite vibrator. Laying on your back on your bed, you turn it on and slide it into your wetness while continuing to fondle your scaly breast. You close your eyes and start fantasizing that the vibrator is a rattlesnake, thrusting its head into your vagina. You don't know where the idea came from, but it really excites you as you rapidly drive yourself to orgasm. As your back arches, you hear a slight rattling sound.
Laying there after your climax, you open your eyes and look down at your right breast, now completely covered in scales. Your nipple has transformed into a little rattlesnake rattle.