...............................The main rule in the arrangement between my wife Sue, her sister Annie and I is that Annie and I never have sex without...Sue being present............ "But Sue is here Mark. Please fuck me now!" She pleads.I glance across to Sue and surprisingly her eyes are slightly open. She winks at me, licks her lips, nods and then puts a finger on them for me not to let on she's conscious. I've got the go ahead!I smile at Annie. "Alright Annie but my rules now. We do this my. She moaned a lot in all this. And pushed me down and came on top and inserted my cock in her pussy, gave a few thrusts in that position and turned to the other side putting her back to me and the started to thrust, this gave my cock full stretch in the right direction, 20 minutes in this position, I pulled her back and started thrusting from below from behind.After about 20 strokes is switched and got on top from behind without pulling my cock out. I fucked her in this position for 15 minutes. Robbie's mouth was wordlessly communicating what boon he wanted. What could be more of a mothering thing than suckling her young, even if he was over sixteen. My heart seemed to pour pure love straight from my beating organ through my nipple to Robbie's lips. I wanted to nurture this sweet physical closeness, like when my boy was a baby. But the growing hunk of manhood between us sort of skewed (or skewered) the image.For his erection was once more rising and that meant his latching on to. YESSSSSSSSSSSSSSSSSSSSSSS!!!!!"I slow my minstrations and let her come down slowly off of her high. Her body kept shaking and trembling violently then slowly subsiding as she came back down to earth. She rolled over and grabbed me tightly and kissed me harder and more passionately than I had ever been kissed in my life. "Oh my god that was fantastic!" she told me once our lips parted. "Well we're just getting started if you're up for more" I tell her. "Oh god am I" she replies.