Lisa and I went inside to check on our guests who lay on our king size bed. Helen and Charles were obviously accustomed to going to bed and getting up early, as they were oblivious to Lisa and me as we crawled into bed. We lay on the bed in each other's arms, stroking each other's back, tenderly kissing. This gradually escalated as my insatiable girlfriend moved her right hand to the front of the gym shorts I wore. As she...