In the here and now, Carla's mouth was still riding her brother's 7-inch pole, and Laurie decided to help her loving sister out. She started to rub a little harder against Carla's back as she inched her hand down and swirled it through Carla's neat blonde triangle, enjoying the moan that she made around Zack's cock, and her fingers went lower, seeking the hot, wet heat, oh yes, and she stroked at the wet bare lips of her pussy.
"Oh yes, so hot so wet, gonna make you cum while you suck Zack's cock, make your mouth tighten up with a sweet hot grip that will suck every drop out!"
Laurie was watching Zack's face, she knew he was getting closer.
"Are you just about to explode sweet brother?"
At Zack's grunted Yes, Laurie started to polish Carla's straining clit, cooing, "Grab his balls."
Zack felt his balls cupped, and Carla's soft fingers started to squeeze gently, coaxing the explosion. He felt Carla's muffled squeals of pleasure around his dick as she crested, and her mouth tightened down on him in the midst of her climax. That brought it on, and he could feel his prick erupting.
Carla was ready for her mouth to be filled, and Zack did not disappoint. The first blast hit the back of her mouth, she quickly gulped it down, the hot sucking action keeping his prick going, and 3 hot blasts peppered the roof of her mouth, 3 more spewed all over her tongue and she savored the taste before she swallowed, and she nursed at his prick, sucking in the last few dribbles of spunk.
Laurie whispered in her ear, "Let me taste it."
Carla pulled her mouth away, and Laurie was right there, lips quickly fused together, and Laurie's tongue dived into her mouth. Carla's cum slick tongue rose up to play, and they moaned into each other's mouth as they shared up the remnants of Zack's explosion.
When they came up for air, Carla cooed, "That was very tasty, wouldn't you agree sweetie?"
Laurie gave Zack a big smile and replied, "It certainly was, next time, it's my mouth that will get flooded."
Just at that time, they heard the door of the attached garage opening, and that broke the sexual spell that had enveloped them.
Zack said, "Sounds like Mom and Dad are home early. We'd better get ourselves to right."
Zack quickly pulled on his clothes, and the whole time, Carla and Laurie let him gaze at their nudity, god what a smoking hot twosome his sisters were.
Laurie cooed, "To be continued, we are both looking forward to more."
*****
Zack hustled downstairs, and his step Mom came in through the connecting door between the utility room and the kitchen, In the few seconds before their eyes met, Zack drank in the vision, god, his step Mom was a real MILF. She was wearing a conservative dress and blouse, what she called her work clothes.