Replace her towel with a much smaller one, forcing her to change into the new bikini

You quietly open the bathroom door and replace Courtney's towel with a much smaller one in hopes that it will make her more likely to wear the bikini you bought her. You then close the bathroom door and give it a knock to interrupt her masturbation, asking her if she's alright in there. You hear a faint gasp before Courtney answers, "Um yes, Ms. Divyne, I'll be out in just a moment!" She shouts with a slight bit of panic in her voice.

After a couple minutes the bathroom door opens slightly and Courtney peeks her head out, "Ms. Divyne, could I get another towel? I think this one might have shrunk in the wash or something."

You shake your head and tell her your short on towels at the moment due to the recent move. You hold up a bag and tell her she can change into the new bikini instead. She nods in appreciation and grabs the bag before closing the door.

A few moment later she peeks her head out again, "Ms. Divyne, this bikini is a bit....revealing. I don't think I can wear this." Her cheeks flush red with embarrassment.

You tell you you're sure she looks amazing and that models who have graced the cover of Sports Illustrated have shown off far more than she would be. You say it's important for a model to be a body positive inspiration for all the young athletes out there looking for someone brave like her to show them what true athleticism looks like.

The redhead stays silent for a moment, considering your words, before she responds, "I guess If I'm gonna be a real model I can't be embarrassed to show of my body, can I?" She nods, "Okay, I guess I'm doing this." Courtney exhales deeply and slowly opens the door, revealing her fit body in the black see-through bikini. She looks at you timidly, her hands fidgeting in a way that shows she clearly wants to cover herself, but she resists the urge and looks to you with nervous interest, "So, what next?"