As Dr.No has stated, you need to have gone to StarCon 3 times have the Slut Route locked in.
- Go to the Nightclub
- Select (Dance)
- Hover over the left bottom menu bar
- Select the Phone
- You can only do this once a day
It is a little buggy as mentioned, and undercooked. So it is possible it might not work for you till resolved in 1.8 without multiple attempts.
Here is a list of the other locations try these if you have the outfits:
- Mall [ Requires “Red Outfit” from Zuri’s shop ]
- Downtown Streets [ Requires “Cool Outfit” from Zuri’s shop ]
- Hospital’s Patient Room
- Outside Ken’s House
- Club [ Slut Route ]
- Park’s Bathroom [ Need “Lost Key” from Tasha’s shop ]