itch.io

First of all, Sofia also has 2 Routes > Love or Slut.

After helping Mario with all of his Resume Minigame, go to the Mall straight away and you'll meet Sofia, asking you on a "date" at the Gas Station. Go there immediately and she'll reveal herself as a Cop, who has been trying to bring Mario down. Since you're already regarded as Mario's helper, she'll ask you to help her collecting evidences on Mario's crimes. Accept her request and you'll be given 2 choices to collect the evidences:

                     1. Getting the evidence yourself / Love Route ( You'll get a recorder from Sofia and just ask bunch of questions to Mario in his Office )

                      2. Get Sofia inside Mario's Villa / Slut Route ( This will trigger Sofia Mario Sharing Route and a must to unlock her Slut Route )

If you choose Getting the evidence yourself: 

                       1. Go to Mario's Villa and ask bunch of questions to him in his Office

                        2. Go back to the Gas Station on Friday to meet Sofia, hand her the recorder and arrest Mario immediately.

                         3. Go to the Gas Station and you'll get a scene with Sofia 

                         4. Go to the Bar at the Downtown Area ( I forgot on what day ) to meet Sofia there and you'll get invited to her House

                         5. Go to Sofia's House at the Seaside Area to have a chat with Sofia. Do this 3 times ( once a day ) until you find a memo on her table

                        6. ( Make sure you already have either Athlete or Living Weapon Trait activated first ) Go to the Evergreen Area and you'll find a new pathway called Shack has been unlocked. Go to the Shack and you'll find it being protected with 2 of Mario's Goons

                        7. Proceed on defeating Mario's Goons and go inside the Shack. There you'll find Sofia being held hostage by Mario who has escaped from jail and wanting to kill her. You can choose to either Knock Him Down or Kill Him instead in order to free Sofia

                        8. Go back to Sofia's House and you'll get more scenes with Sofia ( Love Route Completed )

If you choose Get Sofia inside Mario's Villa:

                        1. Go to the Gas Station on Friday and tell Sofia that you're ready to get her inside Mario's Villa

                        2. Go to Mario's Villa and straight to the Lounge to trigger the Sofia Mario Sharing Route

                        3. Sofia then will excuse herself to "go to the restroom" and trigger the threesome scene again when she come back

                        4. Go back to the Gas Station to speak to Sofia and tell her to not arrest Mario just yet

                        5. ( Make sure you already completed Emma Mario Sharing Route first ) Go back to Mario's Villa and straight to his Office to tell him that Sofia is a Cop. Mario will give some money for your loyalty and wait until tomorrow

                       6.  Go speak to Mario again the next day and you'll be given the Guest Room Key, saying there is a surprise waiting for you there

                       7. Go to the Guest Room and you'll find Sofia, already being corrupted by Mario, waiting for you as her Master ( Slut Route Completed )  

P.S. You can still choose to arrest Mario and proceed with the Love Route even after you did the Sofia Mario Sharing Route. 

P.S. I believe there is a connection between having successfully corrupting Emma first before proceeding with Sofia Slut Route. This is because there was someone saying that even though he already snitched to Mario about Sofia and he has not completely corrupted Emma just yet at that point, he didn't get the Guest Room unlocked as the result. ( Logically speaking > If you do Mario a favor, he will return it the same )