The Perfect Black Rose, part I
This is the most complex of the optional side-quests, requiring a number of actions.
First, get the erotic book from the Bookseller. You need to pass a CHR test before you're willing to purchase it. Bring it to the Coffeeshop and read it twice; this will perk up the Barrista's attention, and after a bit of prodding she'll mention how she's dreaming of someone that looks like the player (except richer and stronger, of course... she really wanted Christian Grey, but he wasn't available). She mentions that she knows it's him, because when he leaves commands he leaves behind a perfect black rose.
To open up Elsewhere, go to Katie, talk about gems, then go to Chloe to find out about the portal in the basement. Next morning, go to the University, recruit Dylan and Katie, and head into Elsewhere to explore. From the next morning onwards, Elsewhere is now open each morning you're not otherwise occupied; you can go in there to have random fights, unlock story sections, and get ingredients to sell. Once you have access to the Random Paths of Elsewhere, look for the card labelled Treasure; when you open one there is a random chance of getting a Perfect Black rose. I wonder what we could do with that?
Head back to the cafe, and read the book again to start getting ideas. You need some pen and paper, which you get from the bookstore (at an outrageous price). Head back to your bedroom, and open your PC. There's a new Browser Icon (the Demonfox browser). Use QuackQuackGo to search for sex toys, and order a vibrator. It'll be delivered to the Crowley the next day, so pick it up from Chloe. Now head back to the Starcucks, and order a coffee. While drinking, you can now set in motion your plan. Come back next day and order a coffee to make sure she's following instructions. Enjoy.