Try external use.

Sarah decided to try applying the pills externally, but that would require some preparation. Unzipping her fly, she grabbed her schlong, still slick and shiny from her brother's pussy juice. Slow strokes made it harden quickly. When it was fully hard and throbbing, she took out two pills and crushed them into powder on her desk. Sitting down on her chair, she began stroking her cock languidly with her right, using her thumb to rub her slit at the end of every stroke.

Her other hand slid up her shirt and began rubbing her breast through her bra, sliding down the cup so she could reach her nipple. Soft gasps rose from her throat as she pinched and rolled her nipple between two fingers, sometimes massaging her whole tit. Her other kept stroking her drooling cock, more pre coating her length and adding to the copious amount of fluids already on it. Lewd slick noises filled her room along with her low moans.

Having cum more than half a dozen times already, she had trouble getting there. But when she started thinking about Katie and what she would do to her, her lust rose rapidly. The thought about covering those cute freckles with cum, stuffing her every hole, filling her with cum and watch as the Growth-X transformed her...

The image of Katie with tits twice as big as her head, sucking on Sarah's engorged cock sent her over the edge. Jumping up, she struggled to aim her twitching dick at her desk and shot one, two, three big bursts of cum into the small mound of powder and all over the lacquered wood. With one finger, she then mixed cum and crushed pills together into a thick paste.