The Invitation

"Me too!" she said, smiling.
"Oh, he definitely likes," said Lucy, looking up from Sally’s neck and studying Jack’s cock. "No doubt about that. I think it excites him. Would you like to see more?" she asked Jack.
He nodded. Sally twisted around to face Lucy and the girls' lips met. This was certainly no kiss of friends - even really good friends. The two girls were exchanging a kiss between lovers, their hands roaming over the clothes on each other's backs. Jack could feel his cock strain against the confines of the lace and sheer knickers as it reached its full size. After a few moments the girls broke their kiss and both turned their heads to look at him.

"Well, that’s enough for now, but anything could happen if you are good!" said Lucy. "Now take off your dress for me – I want to see the whole ensemble."
By this time Jack had pretty much lost not only any remaining shreds of self respect that he had arrived with, but also anything resembling self control. All he could think of was that his fabulously attractive blonde girlfriend was going to make out with her best friend who was herself a stunningly good looking redhead, and that he was going to be allowed to watch.
He turned away from the girls and, looking over his shoulder said “unzip me please?”
Sally straightened up and allowed Lucy’s hands to fall from her breasts and out from the bottom of her jumper. She stepped over to him and reached for the zip in the back of the dress. Jack held his hair out of the way as she did so, unconsciously mimicking every woman asking for help with a zip. He felt the zip descend until it stopped in the small of his back. He knew that Sally and Lucy would now be able to see the horizontal strap of his bra and the lace of his suspender belt. Still facing away from them both the drew the dress forward so that it came away from his shoulders, revealing the bra straps. He turned back towards the girls and lowered the front of the dress slowly, revealing the black lace of the cups of the bra holding his false breasts.