The horniest thing I have ever seen was last week,when my wife Helen finally agreed to let another man into our bed.I have been trying for years to persuade her and her only conditions were that it was a one off and that it was someone we could both trust. We finally settled on an old friend of ours David whom we had both known since high school and had been divorced about a year.When I met David for a drink and explained what I had in mind he didn't believe me at first but when I assured him I was serious and that Helen had agreed,he became very enthusiastic,so we arranged to meet at our house at the weekend. All that day Helen became more and more nervous as I became more and more excited and as I watched her come from the shower and watched her get dressed I noticed she chose her sexiest black bra and panties no tights and a tight skirt which emphasized her bottom which for a 45 year old woman protruded like a black woman's. When we heard the front door bell ring we looked at each other and I kissed her and told her how much I loved her,then I let David in he looked almost as nervous as us,but sat down as my wife fetched him a drink,I noticed him keep staring at Helen's bottom as she poured the drinks.For about 15 minutes we all chatted about life in general and everyone was obviously on edge but as the drinks started to relax us,I said " shall we go into the bedroom" and like 3 naughty children we slowly got up and moved towards the stairs,as soon as we were inside I took Helen in my arms and kissed her on the lips as I had done a thousand times before,only this time David was standing behind her his lips nuzzling her neck.We gently lowered her onto the bed with Helen in between us then it was David's turn to kiss her and I stared as my wife of over 20 years pulled him closer and put her arms round him and passionately return his kiss. For a while it seemed as if they had both forgotten I was there as they explored each others mouths with their tongues,then David was unbuttoning her blouse exposing the sexy black bra that only hours ago I had watched her put on,then expertly he felt behind her and deftly unfastened the clip and pulling her bra free,my wife's soft,white tits were on show to another man,his lips moved slowly to her stiffening nipples and he took each one in turn into his mouth.It was then I noticed the bulge in David's trousers and knew he was as erect as I was,his hand now was on the side zip of her skirt and the button at the top as he opened them both Helen raised her hips And I felt it was my turn to get involved so I in one swift move pulled her skirt off and dropped it to the floor.Helen was now almost naked only her silky black panties lay between her and the man who was about to fuck her,David's hand was between her legs rubbing up and down her almost visible slit her wetness was obvious then as before she raised her hips in an invitation for one of us to remove them,David was there first and as he pulled them off we both saw Helen's open pussy lips glistening,my hand got there first and I slipped a finger into my wife's c**t,I had never felt her wetter.I kissed her on the mouth and whispered how much I loved her then as I turned round I saw David had kicked his trousers off and his erect cock standing out,its purple head looked a lot bigger than mine and I could see a droplet of pre-come shining,Helen opened her eyes and looked down at the the angry erection that was about to enter her.Her legs opened even wider as David slid up her naked body and I stared with pure lust as the head of his cock gently moved forward nudging her pussy lips apart and then he was inside of her and the familiar rhythm began I moved to the bottom of the bed as he raised her legs higher and I could see his balls slapping against her bum with each thrust.I don't remember getting my cock out but I was rubbing it in time with his thrusts,then his balls seem to contract as he thrust even deeper inside her and I knew he was shooting his sperm into my lovely wife and with one last grunt he lay still with his cock still embedded in her. Finally he pulled his wet cock from out of Helen and I saw his and her juices oozing from her and he rolled onto his side panting,I quickly took his place and my own stiff cock slid easily up inside of her and her pussy seemed to swallow my cock which for some reason seemed lost in her saturated pussy after only about 10 thrusts I felt my own hot sperm join David's. After we had all composed ourselves,dressed and returned downstairs David said it was one of the best experiences of his life and thanked us both and kissed Helen on the cheek and for some reason made me jealous,which I know was ridiculous considering the fact that he had just fucked her. After he had left Helen was a bit strange with me at first but eventually admitted that it had been tremendously exciting,but was a one off and didn't want to mention it again.We will see.