Athena's muscles start to grow.

Liz stared as she slowly pulled her dick out with a soft *pop* and stepped back, watching in fascination as Athena's muscles began to swell outwards, each throb pushing them outwards and forcing Athena to grow taller as she moaned from the sensations running through her body, while Liz focused on her dick, throbbing and tingling from this new, and exciting way to use it.

Her finger traced a vein that pulsed excitedly in time with her heartbeat, before prodding the reddened head of her penis, and despite herself, Liz licked her lips, wondering if she should jerk off and make her 12-inch cock grow even larger. Her hands slowly wrapped around the shaft...

Then another moan caused Liz to look up and see Athena shakily rising to her feet, looking down at her new, enlarged muscles. Now, she looked like she had been working out extensively, nearly at a professional level, and her A-cup breasts had swelled into large C-cups with slightly enlarged nipples that visibly throbbed in time with the veins on her body, before she began comparing heights, and Athena's eyes widened as she realised she had grown from a fairly petite 5'2 to a taller 5'9 and for a long moment, the two girls stared at each other.

Then Athena smiled, "So, is that all it can do?" Liz blinked, before her own smile appeared and she gripped her cock and before Athena's eyes, began to jerk off, her hands running up and down in long, powerful strokes as her breath came out in short gasps, before with a groan, she felt pressure building, seconds before her cum flowed through her dick and began spurting out, the stream of hot, sticky and thick semen landing in ropes on Athena, who gasped before looking at the amounts that were landing around her as the still running shower began washing it all away.

"Get ready...ooh!" Liz moaned to herself as her body began to shake and spasm, her seizures forcing her body to grow as muscles pushed outwards, swelling to larger proportions as she flexed her arms to form biceps that swelled to the size of footballs, the rest of her muscles bulging outwards to match, before her breasts surged forward to swell to the size of basketballs, her nipples stretching to flop down at seven and a half inches as Liz relaxed, running her hands over her expanded, massive 6'5 body before parting her breasts to see that her penis has gone flaccid, but was now nine and a half inches long.

Athena stared, wide-eyed, at Liz, "Woah...you grow every time you jack off?" At Liz's shy nod as she realised what she had just done in front of someone, and realised that she had just had sex, before Liz squeaked in surprise as she felt Athena's hands on her nipples, "Damn...what happens if I..." Liz tried to say something but she could only moan as she felt her nipples stiffen, and then begin to slowly swell as Athena giggled, "They're like mini-dicks!" Liz blushed as Athena continued stroking the nipples, watching as they swelled larger and larger before she heard a faint gurgling from her breasts.

"Aah, keep doing that, and you'll get a nice surprise..." Liz moaned and Athena obliged, stroking more and more forcefully as Liz's nipples finished swelling, veins leading into them becoming visible of Liz's breasts as she felt the pressure building and she managed to breath out, "More...more, keep going!"

Athena said nothing but the strokes continued to become more forceful before Liz suddenly gasped as her breasts and nipples pulsed, streams of milk spraying outwards before felt Athena's mouth wrap around one of them and suck forcefully and she looked down to see the girl swallowing after each powerful suck and watched her throat bob up and down entranced, "Wow..." Unable to stop herself, Liz brought up her free breast and began sucking down her own sweet, creamy milk.

Finally, after a few minutes and with stomachs full of milk, Athena and Liz cleaned up and got dressed, Liz stuffing her flaccid dick inside her pussy to Athena's amusement. Finally, Athena said, "So...how do you want to do this?"

Liz blinked, "Huh?"

Athena rolled her eyes with a small smile, "How do you want to do...this? You want to make it a casual sort of thing where we meet up and fuck each other and make ourselves bigger, or do you want to make it serious with hand-holding, public displays of affection, and people calling us lesbians?" She looked up at Liz, her expression becoming serious, "Because...fuck, I liked that, and I think I want to see where this goes."

Liz blushed before looking away, "I don't know..."

Athena shrugged, "Well, maybe I can get a date with your brother."

Liz blinked, "What?"

Athena smiled, "Your brother is hot, and I know there's plenty of girls here who go home with wet pussies after seeing him pick you up after school, and I'm one of them." Her smile turned mischievous, "And if I'm right, you want him as well." Liz's head whipped around to stare at her and Athena pointed at her crotch, prompting Liz to cover it with her hands, "I know a way you can take care of that..."

Liz stared at Athena, who smiled back and nodded shakily before carefully removing her rapidly stiffening penis, and the two girls watched as it tented her skirt, swelling and stretching into thirteen inches of throbbing flesh as Athena licked her lips before pulling down her slightly too-tight panties, "Now then, see if you can do this without making a mess."

Liz nodded silently, and her hands grabbed Athena's hips as the other girl checked her watch, "We can skip class after this, only an hour left in the day." Liz nodded and pressed Athena against the wall, before with a single powerful thrust, **** her enlarged dick into Athena's tight pussy, prompting a gasp of ecstasy, "Gaah, so big...now make me bigger!"

"Okay!" Liz replied as she began thrusting into Athena, grunting slightly in time with Athena's moans. As Athena's pussy clenched around her dick, Liz wondered what it would feel like to have Josh thrusting inside her pussy and she felt herself dripping down her leg while her penis swelled slightly, eliciting a surprised gasp of pleasure from Athena.

Liz was also thinking about Athena's offer, wondering if maybe...Liz's thoughts were interrupted as her balls, each larger than a hacky-sack rose upwards and she let loose a soft growl as her penis began to pulse rapidly, feeling her super-semen rush up it before spurting into Athena's pussy just as the girl orgasmed as well, her pussy sucking greedily on her dick as they both shuddered.

Seconds later, Athena gasped as her muscles began to bulge outwards and she grew taller, her body spasming as she groaned at the sensations, her hands going up to her swelling breasts, and her eyes fluttered open as she felt her now 2-inch long nipples swell before they sank into her aureoles, the girl pulling up her shift to see her changed nipples, "Damn! I get pussy-nipples and you get dick-nipples!"

Liz giggled and seconds later Athena joined her as she flexed her softball-sized biceps before Liz gently set the other girl, now 6'2 and pulled out her flaccid monster cock out with a pop as Athena clenched her pussy to keep the leftover cum inside, her body still swelling outwards as it absorbed it all.

The two girls looked at one another, Athena's eyes holding a meaningful question.