I do have incredible stamina when I want to, and since I had just filled Amber's pussy with a huge load, I knew I could hold out for much longer than my sister expected her mystery man to do. I found a clock hanging on the wall and was laughing on the inside as twenty minutes passed and my sister was still doing everything she could think of to make me cum. I could tell she was frustrated that it was taking so long and I stoked the fire just a bit by gruffly saying, "Hurry up bitch! You said you'd make me cum and swallow it all! Come on,...