Once you beat Erica in the bimbo off [SEE HERE], next time you visit Candy at the café, she'll congratulate you on your win. This will unlock the ability to talk with her about being a bimbo with her in her talk options.
While talking with Candy about bimbo things, always choose the enthusiastic options to move forward. Once you talk about a few things, she will bring up a shopping trip to the mall she wants to take you on. She will want to meet up on Sunday, make sure to make it to the meeting.
On Sunday, head to the mall to meet up with Candy. Depending on how you dressed, Candy will make a comment on it and will then take you to the clothes store to get a sluttier look. You'll then both head out shopping where you'll get the following items:
Slutty pink tube top
Plastic pink miniskirt
Slutty pink heels
Candy will then say that you wont be paying with money but rather some "service". She will then spot two well dressed guys enter the store and ask them to pay for the items you're wearing. As one of them is paying, you'll have the option to start your payment back to him. You can choose to get on your knees (blowjob), or bend over (anal). After finishing the first guy, more will start to enter the shop and an orgy will start. After the orgy, you'll head home.
Please go to THIS page for a more in depth walkthrough of Candies rescue.