Be realistic

You moved your hands back down to her hips and invited her to sit down on the bed between your legs, turning her around so that her back was pressed against your chest. Once she was sat down, you couldn’t help but take hold of her boobs again while placing your chin on her shoulder to look down at what your hands were doing.

“I'm gonna be honest, I do think I can feel a difference but I don’t think it's enough to be worried about. I know you’ve had worries in the past about comparing yourself to Mom and Lucy and although I don’t want to bring up that subject again, I think it’s relevant enough to talk about it” you said, getting a slight nod from Sarah before you continued.

“It’s true that you could go up a couple of sizes but… I don’t think you should expect anything too big to happen. Plus I’ve been serious when I’ve said I like you the way you are and a little more or a little less of ‘these’ isn’t gonna change that” you explained, emphasizing your point by shaking her boobs within your hands.

Sarah stayed silent for a little while, leaving you to continue playing with her body in the meantime. Sometimes letting your hands wander away from her breasts as you marvelled at how athletic she actually was. It felt a bit strange to say you were envious of her body given that she was… well a she, but you couldn’t help but be impressed that she had stayed dedicated to staying in shape. The envy was quickly outweighed by your feelings of making Sarah your own and although you expected to have the same feeling once you saw more of Grace, perhaps you would feel different and want to show her off given her exhibition streak. Your hands had briefly stopped caressing her as you pondered and although unintentional, Sarah seemed to take that as a cue from you to speak up.

“I don’t think I really want to get to the same size as Mom or Lucy now that I’ve actually thought about it seriously. I used to always be envious when I realised I wasn’t gonna get as big as Lucy when I was younger but now I think I’d prefer staying as I am. Sure maybe an inch or two more but other than that I think I’m happy” she explained, turning her head towards you just enough for you to see a confident smile growing on her face.

You planned to tell her eventually that you were the one who caused the sudden growth and now that it had caused her to self reflect and become happier with her body, the guilt you had about keeping that secret from her was lessened by a fraction. With her confession, it didn’t feel like the right moment to just continue groping her like you had been, so you lowered your arms slightly and wrapped them around her in a hug.

You both seemed content to just let the hug continue for a minute or two before your thoughts turned perverted and the contact started to have an effect on your groin. You started rocking slowly left to right and you cradled Sarah in your arms. You could tell she was feeling confused but you continued swaying a little bit further every time until you rocked far enough to push you both all the way to the side so you were both lying on the bed. You had been about halfway up the bed and you laying down with your heads now conveniently set down on one of your pillows.

You felt pretty stupid in retrospect but your idea of getting Sarah to lay down in your arms was complete, even though you could have just as easily asked her to do it. You were sure Sarah could feel your dick pressing against you and she turned herself around to now put you face to face. You couldn’t help but want to kiss her as she looked at your face and with nothing holding you back you gave into your desire, taking her lips and getting a moan of approval from Sarah in return.

Sarah had locked the door when the two of you had entered the room and you were glad that you didn’t have to stop and untangle yourselves as you started getting heated up. You went to bring your hand down towards her pussy and found that she already had her hand inside her pajama bottoms. She didn’t stop you from removing her hand and replacing it with your own, only increasing the eagerness in your kiss when your fingers made the right motion. You continued moving your fingers and caressing her sex, taking note of how she responded to your kiss to determine what she liked the most.

At some point you found yourself taking the lead and placing yourself over the top of your sister, placing your knees either side of her and holding yourself up with your remaining hand. You were happy to continue focusing your attention on Sarah as you carried on kissing but you felt something brush against your crotch and had to break the kiss to look down. With her hands empty, Sarah had taken it upon herself to return the pleasure you were giving her and moved her hands to start unfastening the buttons on your jeans.

Now that you knew what was happening to your crotch, you went back to kissing Sarah and focused on keeping her feeling as good as you were probably about to. You couldn’t help but give a noise of approval as you felt her hand wrapped around your cock and you helped her push your jeans further down your legs to free yourself from them. She started off slow, giving you a few strokes up and down before she upped her pace and got herself into a rhythm that she had used the few times in the past when she had previously jerked you off.

As the pleasure got more intense, you could tell the arm holding you up above her wasn’t gonna last much longer, especially when Sarah’s handjob was getting more pleasurable by the second.

“I don’t think I can hold myself up for much longer. You okay changing positions?” you asked, breaking the kiss with her to mention your worry which she seemed happy to oblige.

Sarah seemed to take the news in stride and with a glint in her eye, she removed her hands from your cock and pushed you over onto your side and then even further so that she was now straddling you. She gave you a quick kiss on the lips again before she moved further down, leaving a trail of kisses as she worked her body down towards your dick. You could tell what her idea was immediately and as much as you wanted to have her lips wrapped around your cock, you wanted to continue working towards the mutual climax that you had both been ramping up to.

Before her lips made it to your crotch and stopped you thinking rationally, you reached out your hand and placed it on her chin, trying to stop her from moving any further down as she looked up towards your face. You could tell she was eager to get you off and although you were more than happy to let her continue, you decided to speak up and make her obey your orders.