Throat

Your sister senses the coming eruption and tries to let up on your cock. Knowing this is a once in a lifetime chance you say fuck that! You place both hands on the back of her head and you **** her mouth back down on your cock. This time you **** her to go down farther than she thought she could go. Her eyes began to water and her face started to turn a reddish blue. But you didn’t care you were going to finish no matter what. She starts to struggle against you and it causes yo to explode wave after wave of semen into her mouth and down her throat. You swear you can see her throat budge as you shoot your jizz into the poor girl. Sis looks like she about to pass out you pull her quickly off your cock . She gasps loudly as she takes in a big breath of air. Your sister falls back on to the carpet slowly taking small breaths and and shaking. Her pussy specially is twitching, so when you reach down there and stick a few fingers in there she cums hard!It seems the skull fucking really got to her. Must of been to much for her she can barley stay awake now...."Did you enjoy that slut?" she just nods and gives you a faint smile.

Gastly appears before you and she instantly falls asleep.. “Are all full of surprises arent you....? Well thanks for that I think me and you are going to get along great. But what will I do about my sis. I cant let Prof Oak see her like this.