A few weeks ago it was my birthday and I was in town shopping with my wife. We are both in our early forties and she is slim and very sexy. She asked me what I would like for my birthday and I said "to watch you being fucked by another bloke". She laughed it off at first, but I convinced her I was serious. On the spur of the moment we went into a sex cinema. It was dark and dingy inside, but we were both incredibly excited at the thought of what could happen.I hoped at the very least she would get to suck a nice big cock with me watching. The cinema was showing a group sex film on quite a small screen. As our eyes adjusted to the darkness, we could see that there were four or five men sat along the back row and several others dotted about the place. We sat down in the last but one row. My wife was wearing quite a short skirt, and I slipped my hand up it and inside her thong. I was amazed to feel how wet her cunt was - it was absolutley sopping with excitement! I pushed a couple of fingers into her and she gently stroked her clit as she softly moaned. Before long, two of the guys who had been sitting in the back row came forward to join us. They sat down and both had their cocks out, and I could see that one of the guys, who was in his late twenties or early thirties, was the proud possessor of an absolutely huge prick which was easily nine inches long. My wife didn't need to be told, and without hesitating she reached out and started to stroke his big cock. The shaft was so thick she couldn't close her hand around it, and it had an enormous fat, round head, glistening with precum. I whispered to her to suck him, but she had other ideas! She stood up and stepped out of her soaking-wet thong, then slowly sat back down on this stranger's lap, impaling herself on his monster cock, a shudder going through her body as she did so. As she slowly rode his cock, the other guy, who was in his forties, stood up and pushed his hard cock between my wife's lips and she began sucking him. He pulled up her blouse and began squeezing her tits and pinching her long hard nipples, which she loves. I couldn't believe that I was sitting there watching my wife sucking and fucking two strangers like a whore - what a great birthday treat! I knew it wouldn't be long before I blew my load, so I stood up and wanked into her face. As I did so, a couple of blokes in the back row stood up and started wanking their cocks over her too. Within a few minutes we all started to cum pretty much at the same time. I came really powerfully and my wad of spunk shot into her face. I watched as it dribbled down her chin and onto her tits. The two guys in the back row unloaded over her, leaving globs of hot spunk in her hair, and the guy she was sucking ejaculated right down her throat and she swallowed the lot. The bloke with the huge cock, who she was riding, let out a loud moan and I knew from the look of ecstasy on my wife's face that she was orgasming as he emptied his balls into her. We straightened ourselves out and left. By the time we got home, I was so turned on by what had happened that I was ready to fuck her. I pulled up her short skirt and pushed her forward onto her hands and knees. It was then that I noticed the sticky cum leaking out of her bumhole - my wife had taken the nine inch cock right up her arse and had let the stranger bugger her right in front of me! What a dirty bitch! I pushed my cock into her stretched, spunk-lubricated anus and shot my load into her, feeling the cum mingle with the huge load she already had in there. As I pulled out, she screamed in orgasm and I watched her dilated anus twitching as the spunk bubbled out of it. What a birthday, but now she says she can't wait until next year for a repeat performance. Neither can I!