With cheerleading skills

At first Amy was at a loss on what to do.
The siblings both seemed totally lost in their world of kinky **** and pleasure.
How could she possibly attract Adam's attention?

But then she had an idea: Years of practice and cheerleading weren't wasted after all, if she could put her skills to good use by enticing Adam and seducing him away from his sister.
Amy had a talent for quickly improvising rhymes for cheer battles, and after thinking for a few moments, she started to chant loudly, causing Adam to open his eyes and look at her with curiosity.

Adam you're total stud!
Your cock is a massive behemoth!
I know that Sarah is a slut.
But are you sure that is enough?

Amy had gained at least some of Adam's attention, the speed of his thrusts had slowed down considerably. But that wasn't enough. She needed him to want her, to desire her. To stop face-fucking his sister, and then to start fucking her.
To take him towards that path, to give him some more incentive, she decided to pull up her top and finally reveal her perky tits, before she continued to sing the next verse.

You're face-fucking your pretty sister.
She deep-throats like she is on fire.
That sure is something to admire.
But is that all what you desire?
Don't you want some pussy, mister?

To visualize to Adam what he was missing, Amy spread her legs and gave Adam a clear view to her wet and swollen pussy.

Adam had often fantasized about his sister's best friend in the past, but would have never dreamed of having a chance with her, not with the insecurity caused by his previously very small penis.
But this was the new reality of his "Growth X" enhanced enormous cock, making everything he could ever want possible. Amy, the hot brunette cheerleader, showing him her fine-looking knockers and her vagina, trying to seduce him with all she's got.

Adam had now almost completely seized his thrusts, and almost the entire 11 inches of his veiny, fat and hulking "Growth X" powered shaft were outside of his sister's mouth. Although to the clear disapproval of Sarah, who's head had also half turned around to see why Adam had stopped the heavenly **** on her mouth and throat, and what he was staring at. Only to discover that the interruption of her pleasure was caused by her best friend showing off.
At first Sarah was very, very angry at the selfish bitch stealing the source of her ecstasy. But when she looked back up at Adam, she could only see admiration, astonishment, eagerness and lust in his face and wide open eyes. And looking back again at Amy, she was reminded of the love she felt for her best friend, and that she would be very happy for her, if she could experience even only a part of the enjoyment and fulfillment that her brother's plentiful manhood had given herself these last minutes.
She was willing to set aside her own needs and desires for the time being, to share this incredible gift and give her best friend a go at it. She released Adam's remarkable rod from her eager mouth with a loud plop, and free of this constraint the exquisite schlong immediately swung upwards, before coming to a rest in a horizontal position, fully extended, throbbing and pointing straight at Amy.

My cunt is tight, my cunt is wet.
A perfect match for your cock, i bet.
Let Sarah be, take me and switch.
Drill me good, make me your bitch!

With her chant finished, Amy quickly moved and started a handspring: Starting from a standing position she wheeled her athletic body forward in a complete circle, landing first on her hands and then straight on her feet, coming to rest just inches away from Adam, right on top of his horizontally positioned rock solid mast. Adam's rigid shaft was now nested right between Amy's long and lean legs, her wet pussy lips sliding along Adam's magnificent and from the excessive throat-fucking perfectly lubed erection, adding her pussy juices to the mix of Sarah's saliva and Adam's own jizz, as her wet lips slide along his length. Amy leaned her upper body forward, pressing her soft tits and stiff nipples right into Adam's chest.

Looking straight into Adam's wide eyes, which showed his astonishment and fascination with Amy's agility, accuracy and body control, Amy slowly moved her face forward, moving her mouth closer to his, slightly parting her lips.

And then she kissed him.