As Stew's body digested the juice instead of feeling bloated or pain or something he started to feel really good. He could feel all his fat rippling and turning into muscle. As Stew's body just expanded everything felt tight as his shirt and pants ripped off his now Herculean physique. His bulge growing as well leaving very little room in his boxers as the tip escape through the top of his boxers. Meanwhile Erin was transforming in her own way. The old sagging B-cups that had been through 2 pregnancies firmed up under her nightgown. As the rest of her body was going under a renovation her breasts were excited to show Stew off their new and improved body and started to grow and grow. Lifting and expanding the breasts greedily clothed themselves with more and more of her nightgown's fabric. The bottom lifting up past her knees, climbing up her slender yet meaty thighs, revealing her panties now effectively a g-string as were stretched across her massive hips, the curtains rose to reveal her navel on her flat thin waist, and then finally her massive breasts stopped as just a little underboob was shown.
Stew just looking at his wife felt his crotch be even tighter as his dick thickened and lengthened. One look in each other's eyes and they knew each other consented, and Stew walked up and towered over his wife. He just lifted her into her arms and it reminded him of when he first held his children as babies considering how light she felt. He just needed one arm as the other plucked off the nightgown. Laying her in their bed Stew just ripped off his boxers as Erin tried her best to seductively take off her panties. The subtle foreplay ended quick and devolved into making out and fucking. Erin sucking his lips and went from guiding his hands to her breasts and ass to clinging onto his massive form. Stew meanwhile went on his way to ravage his wife and have as much fun as he could with her firm, soft, and massive pillows of flesh. All the pleasure Stew was getting almost disappointed them both as he came really quickly, but it was fine as he didn't get soft and just continued on cumming a few more seconds later. Then he came again and again as he nearly had infinite stamina. Over the session both started shrinking as the magic started to dissipate until over an hour later Stew finished and pulled out.
Both were breathing hard but Stew asked "Wanna take a quick shower?"
Erin said "I feel kind of sore, but that sounds good." The two then did as they said and cleaned themselves. It also helped cool down their emotions, and assisted Erin in getting out a lot of the cum that Stew spewed into her. "Think that enchanted juice gave some temporary infertility?"
Stew said "Probably... I think it also had some lingering effects. You look thinner."
Erin chuckled and said "I think I'm a lot firmer too, although my chest, hips, and you know where are sore as hell. You also look a little more muscular as well." The two dried off and looking into the bedroom they knew they would be doing a lot of laundry in the morning as they stared at their bed.