Well sorry that I can't find another way. Its the only way that I've seen work for me.
No, you're cool. I'm sorry for being a dick.
How to have sex with Kitty when you meet her on Day 5:
-Prior to day 5, build up Rouge's stats and save at least 40 dollars.
-Buy "Avenger's Penthouse" and "50 Shades of Grey."
-Go to class, run into Kitty, and choose all her best love options.
-When you first enter class, leave and come back so you can sit next to Kitty.
-Give her the books, flirt with her (touch cheek), and add her to party.
-Take Kitty to her own room, and text Rogue to come join you.
-Ask Rogue to dance, Kitty will join in too. Immediately stop.
-Run through as many sex options as time allows, always yielding, just to build up some stats.
-By midday, go to the pool, hug Kitty, add her to party.
-Take her back to her room again and text Rogue to come join you again.
-Ask Rogue to dance, and stop immediately again. Switch to Kitty and run through any leftover sex options, always yielding.
-When you've asked Kitty everything, stop. Ask Rogue to leave, ask Kitty on a date, and save your game.
-Ask Kitty to study and make out with her. If she doesn't choose to make out, reload and try again.
-Slap that ass and make out until Kitty's lust is at 68 or 69.
-End scene and the time will move to evening. Kitty shouldn't be in the party, but if she is ask her to leave.
-(The hard part) Save your game. Go to the showers and make sure there's no one in there. Take a shower.
-Both Kitty and Rogue will walk in on you. After the shower, leave, save your game and go back to the shower.
-(Another hard part) You MUST walk in on Kitty as she's getting dressed, but she is fully clothed with the exception of her pink over-shirt. If you don't get either of these scenes reload and try again. (It sucks, I know.)
-Hug kitty, then take her on a date. Her lust should be at about 82 or 83.
-Dinner and a movie. Choose steak for her, salad for you, split the check. Choose "Acclaimed Drama" for Kitty, split the bill.
-Take her back to her room and ask to fool around.
-Ask to fondle breasts, and be insistent. Choose keep going, and she'll lift her shirt revealing her bare breasts.
-Reply, "Lovely" and end scene. Her lust should be at 86 or 87. Go to your room.
-Go back to Kitty's room. She should be masturbating. Enter quietly and start jackin' it.
-Kitty should get +12 to lust putting her at 98 or 99. Slap ass.
-Select, "Why don't we take care of each other?" and ask to fuck pussy. Be insistent and she should comply.
-After Kitty orgasms, she will suddenly feel self-conscious and run away. To prevent this, your first option must be the offhand action, "also suck her breasts."
-You can now fuck Kitty as much as you want for the rest of the night.
There are probably other avenues you can take but it will end up looking like something similar to this.