Oh, your roommate has to use a condom because I’m quite sure he is dipping in other pots, right?” I nodded. “I don’t think you are so there’...s no need, right?” I nodded again.She continued, “There is something I’ve wanted to try for a long time and I think I can make it work with you two guys. Just follow my lead as if the other night never happened. OK?”I was a bit puzzled but intrigued, so I agreed.On their next date I made certain to be there when they returned from an outing. I pretended to. Sneeking out I position myself at the top of the stairs so i could look down and see the sofa where her brother was. I could see he had the TV on and was streched out on the sofa as she approached. Looking up you could see the suprise in his eyes seeing his sister coming in and sitting on the sofa next to him. She crossed her legs and let the robe slide open enough that he could see all the way up to the top of her legs leaving little doubt that she was bare beneath the robe and nighty. It. "I wasn't quite sure what she meant by that."I think you're missing one vital ingredient for that," I said looking at her pussy."Of course, I almost forgot," she replied.Crystal told me to stay right where I was and disappeared out of the bedroom. I think it would be fair to say that I had no intention of going anywhere. I lay back on the bed and stroked my cock through her silk panties. I could already see a damp spot of pre cum seeping through.It wasn't long before Crystal re-appeared outside. It was the practice of the firm to send those new starters with driving licenses out in a 3-ton vehicle for assessment. So, one bright January morning I was seated in the cab of a Bedford TK with another new starter and a Post Office driving instructor.Viv, the other newbie, drove us out of the depot through the early morning traffic of Cardiff. It was obvious he was an experienced and accomplished driver. We stopped at the Post Office Main Sorting Office (I was told they did the cheapest.