Neighbor comes over to ask me to get them some alcohol and sees the massive boner she caused!!

My smoking hot new neighbor Beth came over and asked if I would buy her and her girlfriend some liquor as they both just turned 19..
I was beating off when she knocked on the door and I slipped on some shorts and a tshirt and went to the door. Beth was standing there in the string bikini she was wearing earlier, I stepped out onto the porch and as she is asking me to buy the booze she is kind of bouncing up and down being really flirty.. The sight of her incredible tits in that super tiny bikini top, gently bouncing around causes my cock to go rock hard. The problem was that my shorts prevented it from standing straight up and instead it stuck straight out making the hugest tent in my shorts.
She looked down at the huge bulge from my cock sticking straight out and then looked up into my eyes and let out a small chuckle as I turned bright red. I said I would buy them whatever alcohol they wanted. She thanked me and said she would come back with a list and some money. She looked down at my still rock hard cock and flashed me a devious grin as she turned and walked away. I turned around and began removing my clothes as I went through the door. I began furiously beating my cock thinking about her and her tits!!