The day started like any other, I woke up around 6:00 am, took my shower and went to work. About 8:30 my cell phone rang, it was my sister-in-law Debbie. She was working on some projects around the house, and asked if I could stop over on my lunch hour to help her out for a few minutes. I told her I would be over about 12:15. I left for lunch a little early, and headed to her house. When I walked in the door, she only had a couple of simple electrical questions for me, and we were done with that in a few minutes. She asked if I wanted a beer, and I accepted. We sat at the kitchen table drinking a cool one and chatted about this and that. As I sat there talking with her, I couldn't keep my eyes off of her tits. Debbie is a sexy woman, a couple years older than me, with 40DD breasts, slim waist and great hips and ass! I have wanted to suck on her tits for years. While we talked the air conditioner kicked on and the vent was blowing right on us. It was hot and the cool air felt good, but it caused Debbies nipples to swell under her t-shirt. Seeing this caused my cock to stir in my pants. I decieded I needed to slip into the bathroom and jack off quickly, or I wouldn't be able to work the rest of the afternoon. I excused myself, went upstairs and stepped into the bathroom. I closed the door, but didn't notice that it opened back up part way. I opened my pants and pulled out my swelling cock. I stood there leaning on the sink, slowly stroking my cock. I was just getting into it when I heard Debbie say to me from outside the door in a low lusty voice, "Oh my, why do that alone when I'm right here to help out?" I looked up as she pushed the door open. My jaw hit the floor when I saw that she had removed her shirt and pants and was standing there in just her bra and panties. She had her hand between her legs rubbing her pussy and licked her lips while looking at my cock. She reached out, took my hand and pulled me to her bedroom. She lay back on the bed, removed her panties and bra, spread her legs and started to rub her pussy. I just stood there with my cock in my hand watching her. Debbie told me to take my cloths off and join her on the bed. I was there like lightning. She told me she wanted to watch me jack off while she played with her pussy. We slowly stroked ourselves for a while and I couldn't take my eyes off her fingers rubbing her swollen pussy lips and clit. Her eyes were locked on my hand sliding up and down my cock as well. I moved closer to her to get a better view, and suddenly the musky scent of her pussy filled my nose. Damn she smelled so good, I just kept inching closer to her pussy. I couldn't help myself, and leaned down and let my tongue tickle the hairs just above her clit. Debbie let out a little moan that encouraged me to move forward. I ran my tongue over her enlarged clit a few times and she moaned louder. I was about to plunge my tongue into the depths of her pussy when she suddenly said "we really shouldn't be doing this, you are married to my sister after all!" I gave her clit another lick and asked her "do you want me to stop?" She let out another moan, and said, "I guess oral sex is ok, what she doesn't know won't hurt us right?" I answered her my slipping my tongue between the lips of her pussy and licking her lips rapidly. Debbie moaned loudly and pulled my hips over to her and sucked my cock into her mouth. It only took seconds to get into a steady rhythem of licking and sucking. Her lips and tongue felt incredible on my cock, and her pussy tasted sweeter than honey. I asked her to squeeze my balls while she sucked my cock, then sucked her clit into my mouth and bit down on it. This caused her to squeel and suck my cock harder. One more bite on her clit and she was over the edge and cumming all over my face. Debbie had the wettest pussy I have ever eaten. As her climax subsided, I realized I still haven't sucked her tits like I have wanted to for so long. Just as I was getting close to orgasm, I pulled my cock from her mouth, got on my knees and let my load go all over her huge tits. She squeezed her tits together and let my cum shoot all over her nipples. When I finished shooting cum all over her, I lay down next to her and began to suck my cum off her nipples. I licked and sucked both tits clean, then licked and sucked them some more. Debbie had another orgasm while I sucked on her tits. We lay there quietly for a few minutes until Debbie told me that she has never had anyone suck cum off her tits before, and that she had never had an orgasm from someone sucking on her tits before either. The thought of a guy sucking his own cum from her tits made her so hot she came again from the stimulation. We agreed that what we did was wrong, but somehow I don't think it will be our last encounter. She asked if she could call me again if she needed help around the house, and I told her I was always willing to help. I'll let you know what happens next.