At this point Sarah got wobbly legs, something she gets when she is really turned on, and so she turned to me and legs apart straddled me and rubbed her soaking wet pussy up and down my cock while she turned her head and played with Simon's cock at mouth height before starting to suck gently on his erect penis. I eased my cock into her and started to gently fuck her and suck her nipples as she continued to suck Simon off.
After a while of this amazingly erotic scene Sarah got off me and sat beside me on the sofa seat. She opened her legs wide putting one leg over mine and started to play with her pussy. When she is turned on she finds it almost impossible to keep her hands way from her cunt and she just keeps rubbing her clit the whole time and looking at us as we play with our cocks and stroke her thighs and breasts, which we continued to do.
Simon knelt on the floor in between her legs to be in a better position to stroke her inner thighs and push his fingers occasionally up into her pussy and Sarah leant back watching him as she rubbed her clit above his probing fingers. Her other hand was gently wanking my cock as I watched the two of them play and stay at a heightened level of arousal.
We don't normally actually go as far as Simon fucking Sarah, in fact it was incredibly rare, I might fuck her for a short time in front of Simon while we were playing, but mainly we play in a threesome until we have had enough and then Sarah and I would go to bed and screw to finish off. This evening, with Simon kneeling between Sarah's parted thighs and nursing an erection, I had the feeling that I would like to watch another mans cock slide into my wife's pussy as I sat just inches away, so I suggested it.
Sarah immediately increased the speed of action with her fingers over her pussy so she obviously was attracted to the idea, but she said no at first. Simon came up one his knees with his erection pointing towards Sarah's by now sopping pussy and she stared into his eyes as though daring him. With the hand she was using to stroke my cock she opened up her pussy lips as Simon eased forward so that the tip of his cock was in between her lips. Sarah repeated that she had said no but she eased her thighs up and down in a slow rocking motion as Simon's cock first moved from sliding up and down her wet pussy, to the tip being at the entry of her vagina, to slowly being slipped inside her. She just kept looking in his eyes and just kept moving her hips slowly up and down as his cock slid further and further up her until finally it was all the way inside her. She finally gave into her horniness and put her head back with her eyes closed and begged to be fucked.
Simon lifted her legs onto his shoulders and started to fuck her in earnest. I loved the way her beautiful breasts moved up and down with each thrust into her, inches from me, until finally he withdrew and ejaculated onto her heaving stomach.