This happened a few days ago when the mother in law popped in during the day while the wife was at work. I have never really looked at or thought of the mother in law in a sexual way not because she is unattractive or anything just that she is my mother in law. Anyway the door went and it was 'J' (the mother in law) she was passing and thought she would call in. I let her in but couldn't help noticing she was wearing a tight fitting white strappy top but no bra (never seen her dressed like this before). I tried not to make it too obvious that I kept staring at her tits and just behave as usual so I went to the kitchen to make her a cup of tea. While making the tea I was telling myself to look her in the eye and not the breasts. I took the tea in to her and it was impossible not to notice that her nipples had become erect and were poking through the top. Well the sight of these large nipples started to make my cock rise and despite my best efforts not to I was fully erect in seconds. Hoping she hadn't noticed I quickly sat back on the sofa while rearranging my shorts at the same time. I thought she hadn't noticed but she said looks like your cock has the same problem as my nipples. I went bright red and apologised explaining that seeing her nipples poking through her top was too much for my cock to take. she stood up put her cup on the side and said I think I better take care of that for you then and with that dropped to her knees and tugged at my shorts and boxers until they were down by my knees. she took hold of my hard cock and slipped it straight into her mouth. She took the whole length straight in and began to move her head back and forth so her lips were sliding up and down my cock. occasionally taking it out of her mouth to run her tongue over it and my balls. I didn't really know what to do but was enjoying it so much there was no way I was asking her to stop. I reached into her top to feel her tits and rolled my thumb over her hard nipples which made her shriek and speed up the rhythm she was sucking me. I pulled her top up and she stopped and took it off. the sight of her 50 odd year old tits almost made me want to come there and then but I managed to hold back. I reached down to put my hand up her skirt but she smacked it away and said no you are only getting a blow job. I said ok and carried on caressing her tits and nipples and while she was enjoying it slid a hand back up her skirt. time I managed to get inside her sopping panties and slide one finger into her pussy. it was then she seemed to realise what I was doing and moved my hand away and said no pussy. By now my cock was nearly ready to explode. I told her I was close and she said not in my mouth and really went to town on my cock. I was trying to leave it to the last second before taking my cock out of her mouth and cum all over her face and tits but I lost control and sent the first of three jets of spunk right into the back of her throat. I pulled out and fired another to jets of jizz onto her face. I had never cum so much before and didn't realize I could. she had me so turned on. she swallowed what I had put in her mouth and carried on gently sucking every last drop out my cock while the spunk on her face was dripping onto her tits. She said that was the biggest load of cum she'd had in years. It was a truly awesome sight and really unexpected. I apologised for cumming in her mouth and she said she was glad I did lol. she began gathering up the cum off her face and tits and sucking it off her fingers. She put her top back on and I offered her a shower to clean up but she said she wanted to leave my spunk over her for the rest of the day. I told her I would really like to fuck her pussy but she said not going to happen so I said well at least let me return the favour and go down on you. She smiled and said we'll see finished her tea and left.