sbmorphical:

She quickened her pace as she crossed the street, feeling the first
tinglings of the change beginning. At first it was just a warm flush
creeping up her neck. Soon her clothes began to feel tighter, her
breasts fuller, and there was a worrying dampness on her nipples. She
looked down and suppressed a groan as she saw an expanse of cleavage
blocking her view of her lower body, which was no doubt expanding as
well. She had waited too long between milkings, and she knew she didn’t
have much time to make it to someplace private.