You might have an idea or two

You grab Vanessa's hands and guide her into the bedroom. As you stand in front of the giant bed that fills like 85% of the room, you realize what is going to happen. It's not like you didn't really realize when grabbing Vee's hands, but that was almost out of instinct, completely out of desire. It's first now that your cerebrum catches up with your sub-consciousness.

You're going to have sex with this woman, aren't you?

Yep.

Vanessa blushes as she zips down her tracksuit. She's done that tons of times before with you around, but it has a different meaning to you now. It's not just simple undressing for comfortable sleepwear. It's trust. Absolute and loving trust.

As Vanessa drops her onesie tracksuit onto the floor revealing her body, you almost feel like swooning.
Usually Vanessa has her hair set-up into a ponytail, but not now. She has let her gorgeous long blond hair fall down to cup her breast. Her black sports bra and panties in full view of you. Her perfectly toned stomach actually competes with her breasts for your attention. Her lovely green eyes shining through the bedroom like a beacon of pure joy.
Jesus fucking Christ, she's gorgeous.

You quickly pull your sweater over your head and off your body. You can feel your breasts jiggle as they are freed. You fumble with your jeans in what feels like an embarrassingly long time, but you get them off sure enough.
Vanessa giggles at the sight of your eagerness.

"Yeah, sorry I couldn't strip as seductively as you." you smirk.
"Don't be. You've seduced me already."

You leap into each others arms. It's just a hug this time, but when you both are only wearing lingerie it becomes a lot more.

After some time Vanessa looks at you once again and says: "Well, should we get this show on the road?"

You grab her and you kiss her. The kiss is sloppy and desperate, but you're pretty sure it's the hottest thing you've ever experienced. You both fumble with each other's bras for a bit. It's surprisingly hard to get a bra off, while trying to paint saliva over the canvas that is the inside of another woman's mouth. You both succeed at almost exactly the same time, and as your breasts adhere to the laws of gravity the inevitable outcome of lesbian intercourse solidifies.

You pull out of the kiss. With your torso exposed you get chills. You're not sure if it is because your skin is exposed to the cool apartment or if it is the lovestruck embarrassment of Vee's gaze.
"You have a really lovely pair of breasts." Vanessa says while sheepishly looking down. It wasn't an especially lewd comment, but the tension in the room grew considerably with that comment.
"Uhm... you too." you reply. Wow, what a great response. Not awkward at all.
"I'm kinda envious. They are a lot bigger than mine."
"Please don't be. Your breasts suit you perfectly. Also, being as sporty as you are would be a lot harder with these things walloping around."
She giggles. You love it when she giggles.

Vanessa moves across the bed, and as she reaches the back wall, she lies on her back, and pulls down her lingerie. While the final piece of clothing comes off of her flawless body, you find yourself with no other aspiration in life than to dive down, and mingle with her in every way possible...

... but you can't. The darkness is back. The darkness that has infested your mind and has inhibited you to move forward. The guilt. The doubts. This awful feeling that you have used Vanessa to make you feel better about yourself. She is right there. She is naked. She is presenting every orifice to you. She is blushing and looking at you lovingly. She loves you. She loves you. She loves you. She is there for you to claim...

"claim"

What an awful word.

Is this how you think of her? Like she is some item you can redeem? Vanessa, on isle 2, in the damaged goods section. Have you just bought her wholesale? Have you used her tough situation and her love for her sister as leverage for a romantic relationship? How hollow does this room feel right now?

"Are you okay, Astrid?"

You don't say anything.

"Is this about what I think it is about?" she asks.

You just look down.

"I'm sorry." Vanessa says sympathetically.

"For what?" you ask. This is your fault.

"I'm sorry that I made you feel this way. I'm sorry that I doubted you on the first day we met. I planted the awful idea that you might be doing this for your own selfish reasons ever since I asked you why you were being this nice."
"But you were right." you interject: "Why did I do all of this? And now you are here, naked, and I can't help but feel like a sexual predator."
"I know why you did all of this. I didn't on the day we met, but I do now. You did this, because you are a good person. Not only that, you are the kindest, most generous, almost irritatingly perfect human being I've ever met. I love you, Astrid. There is nothing predatory about having sex with a person that loves you as much as I do. Remember when you told me that Ollie and I moving in was a selfish request from your side? It's the same thing here, but in reverse. I want you, Asta. I want you so much. Please, just help me fulfill this request. Please be with me. Please let me love you, and let yourself love me. It hurts to see you feel this bad about loving someone. There is nothing I want more in the world than to help you fix that."
Vanessa is in tears. You did this. Your insecurities got the better of you. It's time to make things right.

You climb across the bed over to your lover. You crawl over her body, and you near your face to hers. Vanessa lower her hands down and pulls down your panties. You step out of them, and to the best of your abilities use your feet to hurl them to the side.
Vanessa pulls you into another kiss, and your arms and legs give under. You are now laying on top of the woman you love, both naked and kissing each other vigorously. You want to see her happy, and the way she is enthusiastically kissing you, makes you think that she is. However, you want to make her even happier.

You pull out of the kiss, and your head moves down her body, planting a couple of kisses on her firm breasts and her toned stomach before making it to the quote-unquote holy grail. It's an innie like her sister. A cute little slit protruding from her inner depths. You can see a few drops of vaginal tears glistening in the low bedroom light.

You pierce her with your tongue.

You have no idea what you're doing, but your lack of experience is more than made up for in your overwhelming excess of passion and enthusiasm, and it doesn't take long for Vee to start moaning.
"Oh, god... hmm..." you hear, and it just makes you want to please her even more.
You go all over the place. Clit, labia, licking, kissing, even trying to penetrate her as deeply as you can with the limited range of your tongue. Vanessa starts to arch back in pleasure, as she grabs the back of your head. She immediately makes up for her "aggression" by stroking your head and hair as you try your best to bring her to a climax.

It doesn't take you too long. Vanessa screeches in ecstasy.

"Thanks for that, honey." your love says to you: "It's been so long since I last had an orgasm."
"Anything for you, Vee."
"What does UV have to do with this?" she asks confused. Oh no, here we go again.
"No, "you, Vee"."
"I know, I'm just teasing." Oh, thank god.

Vanessa sits up. "Right precious, now it's my turn to please you."

Before you manage to say anything she playfully tackles and towers over you.
She grabs your left breast and she starts eagerly sucking your nipple as if she is expecting milk to come out. You wonder whether she might have a bit of a breast fetish. As she alternate between the breasts, she uses her free hand to caress your vagina.
Unlike the sisters your vagina has a bit more... meat to it, you guess? The lips are more exposed, and while it looks a bit more messy, it also looks more natural in a way. You don't know what type you like the best; you're just kind of happy that the variety exists.

What she is doing is immensely pleasurable. You actually have no idea how experienced Vanessa is. You know Ollie is not very experienced, but it's never been a point of discussion with Vee. You don't want to bring it up now though.

Vee looks like she is getting almost as much pleasure from this as you are. She must really like big breasts. Her furious fingers rapidly entering and exiting your nether-region stimulates you on a very basic carnal level, but her eager suckling stimulates you on a more abstract caring, loving, almost maternal way.
"Oh, shit... yes... I love you Vanessa." you manage to stutter through the pleasure.
"I love you too, Asta." Vee quickly responds before diving back to your breasts.

The world turns completely white in a split second as you climax.

You spend the next hour lying next to your naked girlfriend. You talk, kiss, nipple each others breast, and just feel great in each others arms, until you realize that it is just a matter of minutes before Ollie will come back, and you get clothed.