There's an inbox feature on BikiniFanatics - this feature allows you to send direct messages to others users and models.
Simply head to the person you want to send a message his/her profile and locate the "Send a message" button right below his/her username.
Simply click it and you'll be sent to a message field where you can draft your message.
You also have an inbox which can be found on the top right hard corner of the page. Simply locate the envelope icon, click it and you can see your sent messages and your inbox.