A few hours at least

After Siora leaves, you are left to your own thoughts. All you can hear outside is the occasional chirping of birds. Unfortunately it doesn't look like anyone will be coming by the window to rescue you any time soon. Even if someone happened to pass by, your mouth is still stuffed with Siora's panties. You wouldn't be able to yell to get their attention. The second, less obvious effect of the panties, however, is the smell. You didn't notice it at first, but these are Siora's used panties. As your saliva slowly soaks the fabric, her scent fills your nostrils. Eventually that smell gets so strong it's almost overwhelming. It burns into your nostrils so that you can't forget it.

You aren't sure exactly how long you're left alone. Your only indication of the passing of time is the movement of the sun out the window. You notice the light change direction after what must be a few hours or so. For a while, a small bird lands on the windowsill. Without much other means of distraction, you spend a while watching it rest and clean its feathers. The bird is suddenly spooked and flies away, however, by the sound of the front door slamming open.

"I'M BACK!" you hear Siora exclaim as you hear her struggle to get her shoes off. "And I've got something for ya!"