Ye! I was really enjoying Alex's line, so I focused on her, first. I'm gonna run through the entire method to unlock Corruption: Alex for Lin, so forgive me if I tell you things you already know.
- Alright, to start out, Alex needs to be at Corruption 5. Haily needs to be Corruption 2-4.
- On Saturday Afternoon, talk to Alex and Haily in the living room and join them in the hot tub. Choose "Do you want to check?". By default, you won't have "Alex's Love" because that's unlocked with Lin's Corruption: Alex. This will then fulfill the requirement of having Alex say no.
- On Saturday Night, tell Alex that you watch porn. This will trigger the Porn Date with Alex.
- On Sunday Morning, talk to Lin in her room. Ask if you could get her help with something, choose "Alex...", then choose "You two seem tense".
- After all that, when you go to see Alex on Sunday: Midnight, a second option will appear after clicking on her in the forest. That's when you select "Lin had concerns about Alex". And boom: Alex and Lin Porn Date.
- At the porn date, select "Fuck", then you'll...well...fuck them both.
After all that, Lin's Corruption: Alex will unlock! (I hope)