The truth in Megan's words suddenly dawns on Will and he realizes that there's no way out of his current situation. At that moment Megan manages to get the two dogs pushed into a corner of the room, effectively trapping Will. With the struggling female unable to go anywhere, Sarge easily climbs into position and rams his dick into her waiting sex. Will yelps as he feels the sudden sharp pain signaling the loss of his virginity, followed by the steady pumping as Sarge begins fucking him hard and fast.
"How does it feel Will? How do you like being pumped like a bitch? I think I'll call you Wendy from now on" Megan laughs.
But Will (Wendy?) is only half listening. As much as the thought of being fucked by a dog scared and disgusted him (her?), he (she?) found herself unable to deny the intense pleasure that was now coursing through her entire body.
"That's it boy, fuck her good." Megan said as she lounged on the bed to watch the show.
Will's mind grew hazy, his thoughts indistinct, while Wendy's instincts rapidly took control. Groaning in pleasure, she threw her weight into her forepaws and pushed back against Sarge's thrusts, forcing them to go deeper and deeper. She panted heavily as he fucked her harder and faster, she could feel his knot expanding inside her cunt and knew he would soon tie with her. Sarge's excitement grew and grew, Growling lustfully he grabbed Wendy's scruff in his muzzle holding her gently but firmly as he went on screwing her brains out. Suddenly, Wendy felt her climax hit like a tidal wave. Her head tilted back as she howled in extacy, her body shaking uncontrollably as her pussy spasmed wildly around Sarge's thrusting shaft. A moment later Sarge's voice joined hers as he buried his entire length inside her and released spurt after spurt of thick dog-cum.
Wendy stood still, panting happily, enjoying the feel of her mate's long thick cock filling her. She couldn't remember ever feeling this good in her whole life. She was feeling so good that she barely even paid attention to the human as it was speaking to her.
"Well you certainly look like you enjoyed that... That's good, because one thing I forgot to mention is that sex makes this potion's effect permanent."