Lisa grasped Tomtom's fur as hard as she could with her changed hands and feet. Claws digging into her mate's skin.
Adrenaline flowed through her and an exhilirating feeling welled up inside her, 'she was running away from her home, her life, her humanity, her past to be with her love, her mate, her future.
Below her she could feel his heart pounding and chest heaving. Poor fella had been running through deeper and deeper forest for 20 minutes now.
"Stahp!" She sqeaked and Tomtom skidded to a halt panting heavily.
Gingerly, Lisa rolled from his back, dropping to all fours and standing up after a moment. She took a moment to rotate her head and take in the new sounds of the forest. Rustling leaves, creaking wood, whistling wing and a babbling stream. She scrambled awkwardly towards the sound of water, dropping to all fours for a spell every few steps.
The stream was 20m away and she called over Tomtom as soon as found it to let him drink deep, while she sat with her foot-paws in the stream and rubbing her extended belly.
"Filled wif cum now. Soon will be filled wif growin' wrat babies!" She grinned happily. Tomtom came over and sniffed his made and chuffed happily, rearing to his full, enormous height.
Lisa gasped as she saw his erect member when he did.
"Oh Tomtom! Forgot to turn off your boner...". It would be stuck like this. Constantly hard, hair-triggered and with an unending supply.
"Oh I'm sowry Tomtom", Lisa groaned, she couldn't go back now. One, Eric's mom was home, and two Tomtom was far too exhausted to run.
"Hafta get you off somehow love!" Only Lisa's pussy was raw from fucking, and her stomach was full to the brim of cum, any more and she'd surely gawk.
She could give him a handy... or...
Lisa grinned, she had another hole to use. One she'd never used that way before. Not even with Eric.
The thought of using it in this way had never crossed her mind before, but now, her inhibitions gone, she longed to try it. And of course, she could give a virginity to Tomtom this way.
Flipping onto all fours she raised her pert ass to Tomtom, tail held up and to the side.
" Tomtom! I want you to fuck me in da ass babe!" She grinned like crazy.
Her giant lover wasted no time positioning himself. A slippery tip began rubbing at her soft ass cheeks, oozing cum and coating her ass crack with the goo. She left her rat lover at it for a while, thoroughly lubricating everything before he even made an attempt to enter her.
Eventually his pointed tip stopped brushing over her rosebud, and actually pressed into it. The pointed tip easily slipped in, and Lisa felt his hot ejaculate within her cavity. This lubricated everything further, and let him slip deeper and deeper into his mate.
For Lisa it was a totally new and novel feeling. One eye shut and she shuddered at the pressure building. It felt strange, full, stuffed, not pleasurable the same way being fucked in the vagina was, but not unpleasant either.
Tomtom, gentleman that he was, began his thrusting very slowly, giving Lisa time to get used to the feeling. For her though, the pressure rose and rose, as Tomtom kept cumming, heat from his semen making its way from her rectum, up into her bowels, slowly but surely.
Lisa began to tingle as she was being filled up from bottom to top with rat cum. As she did, she knew this would be enough to change her fully. The volume that would be inside her soon couldn't do anything but change her. Rather than scare her off though, that thought spurred her on, and she began thrusing with Tomtom, matching his movements.
Her hips cracked first, with her hind legs changing next. Bones ground, tentons stretched and muscles grew as everything re-arranged itself.
Several minutes of squeaking later her shiny brown fur had grown in, leaving her fully hirsute. Her face cracked next as her muzzle grew again, this time fully protruding and changing into a rat's head. Finally, her body absorbing all of the relentless supply of cum, Lisa's chest barelled out, rounding her out and turning her body, finally, fully into a giant rat
The final change blew through Lisa in a wave, she knew it was done now, she was a rat and would forever be one with her lover and mate. She let out an exultant squeak, no longer able to form words. With that noise Tomtom pulled out, instantly laying down and rubbing himself with his paws.