Go through the large gold doors to 'Nice Street' (near the Swingles Van). Go to the far right of the doors and you will see a man in a green mohawk. Talk to him and he will offer to sell you the following extra bonus options.

Naughty 1 (makes Switch Ione, Analisa, and Elle May wear bikinis instead of their normal attire)
Loading Screen 2 (naughtier loading screens for Zana Luba and Harriet)
Bonus Art 2 (miscellaneous loading screens, etc.)