Soapy doubles

I play tennis and have always got on well with Sarah, one of the most attractive woman members at the club. Sarah is about ten years' younger than me (I'm early 50s), very fit, pretty with short blond hair, small tits and a gorgeous bum. We often play mixed doubles together and do well, enjoying each others' play and company, celebrating wins with a hug and friendly kiss. Last month however things moved on to a completely different level. I had builders in my house and there was no hot water. I had been planning to shower at the club after our match but Sarah suggested I come back to her house, have a shower and some lunch. I readily agreed and after we had finished playing, I followed her to her place. When we arrived she poured me some wine and suggested I use the bathroom off her bedroom as it had the best shower, adding that she would bring a towel in for me. I stripped off and got in the shower which was indeed very good. I had left the door unlocked and as promised Sarah came in to the bathroom - I heard her and saw her silhouette through the frosted glass of the shower screen. "Here's your towel", she said "do you need anything else?" "Only someone to wash my back" I joked, but to my amazement she replied "Sounds like a good idea to me, hang on a minute!". Thinking she must be joking too I went on washing my hair and was taken aback when I felt a rush of cold air as the shower door opened and then Sarah's voice said 'Move up a little, it's a bit cosy for two." Sarah stood behind me but rather than washing my back, she put some shower gel on her hands and reached around me, stroking my already semi-erect cock. The bold and totally unexpected approach was highly erotic and I was rock hard within seconds. "Mmm, nice" she murmured into my hair as she went on gently massaging the full length of my shaft as well as my scrotum. I half turned and we kissed, before she knelt in front of me and took my cock in her mouth. Sucking vigorously she paused only to say "Give me your full load, I want your cum!" As a guest I felt I had to oblige!