Seeing the option in the menu, Jeff hesitated for a split second before pressing and confirming that that was what he wanted, the computer glowed in response as a growing pain lead to Jeff passing out.
Waking up, the first thing he noticed was something rough rubbing against his… nose? Everything was dark, asides from the fabric of pyjama pants being barely visible amongst the two round globes he was buried between, it had worked, he was… an inanimate ass now, completely normal to anyone except him. His sister was a late sleeper, so it made sense that she was still asleep. After waiting for what seemed like hours, his new home jostled, as he heard groaning from above - the pants rubbing against her butt, causing her asshole to twitch, a very strange feeling for Jeff certainly, as her clambering out of bed brought you out as well.
One step became two and two became four as she stepped out of her room, the barest light of the ambient environment and her pants being your only company as she went to…