It worked, sorta

"God, did my breasts really look this incredible?" Stephanie whispered, clutching her former tits that now hung from her husband's chest and squeezing them.
Tyson smiled bashfully as he watched his wife play with his new breasts. He remembered being so enamored with them back at this age. The two seemed impossibly young, Tyson's body so nubile and easily aroused.
Tyson and Stephanie were too old when they decided to have children. They tried lots of things but nothing worked and they had almost resigned themselves to being childless when they found an old woman at a market who gave them a spell. It would allow them to go back in time and possess their younger selves when they were more fertile.
And it worked, in a way. But Stephanie and Tyson each found themselves in each other's bodies. They'd gone back in time to their first date. Only this time they already knew each other and it didn't end with just a kiss.
Stephanie feasted on her former breasts as her cock shot to attention. Tyson felt himself becoming turned on at the sight of his old body, so hard and eager. A slippery warmth took hold between his legs. He let her lead, taking his sexy body, grabbing greedily, kissing and suckling his delicate form until he was on fire, his pussy sopping wet with desire. Tyson felt himself parting for her and he sighed as his familiar cock filled his strange new pussy. He was delighted by the way his tits bounced every time Stephanie thrust up, delighted to feel her thick cock inside him, delighted as her orgasm pulsed through him, jetting hot spurts of cum into his wet canal.
He wasn't too delighted to find that the spell left him inside Stephanie's now pregnant body, and the two would have to stay as each other forever.