:Submission Fantasy:

The girl fits another leg to the gynaecological chair, this time strapping down your penis, the size and weight of a third leg. With that she looks satisfied and undoes enough straps for you to sit up. She brings out a selection of food: doughnuts, cake, pizza and milk shakes.
"Are you trying to fatten me up?" you ask.
"Yes!" she beams back at you.
Whatever's happening, you're starving and eat plenty.
Sitting up for the first time in a while you look down at your body, and realise that other changes have been taking place, aside from your distended penis.