My wife's sister has always been a turn on for me, and on more than one occasion she has hinted that she was willing to play around a bit. At first I really didn't take her serious, but it did get me worked up even if it was just flirting and nothing else. She finally convinced me of her sincerity to play around one evening when she brought over some Tupperware my wife Karen had ordered at my sister-in-law's neighbor's party.

I was in the garage just piddling around when I heard her call out, and knock on the front door. Since my wife was visiting a friend of hers from work, I had to stop what I was doing to see what she wanted. There on the front porch was my sister-in-law Kathy, with her arms loaded with plastic bowls and crap. I hurried over and opened the door to let her in, and offered to take the load from her, but quickly turned her back to me. "Here, in my back pocket are my car keys. Be a sweetie and get the rest from the trunk, please."

It wasn't hard to figure out just what pocket her keys were in, as they were outlined quite clearly in her very tight, but also very hot jeans. I purposely reached into her left pocket and felt around for the keys, and then with both hands I reached around and checked out her front pockets. I heard he suck in a breath real sharp, and I assumed I had hit a sensitive spot. I lingered a bit before I removed my right hand, and then slid it into her right back pocked, while leaving my left hand in her front left pocket.

When I pulled the keys free, I rubbed my hand across her right butt cheek and gave it a little squeeze as I then pulled my right hand free. Without saying a word I scampered out to her car and grabbed another large box that had my wife's name on it.

Once back inside, I stood holding the box while Kathy separated the items by the names of the people my wife had placed an order for. When she finished, she glanced over and saw that I was holding on one box, and asked. "Greg, where is the other box? Didn't you get the one from out of the back seat like I asked?"

Before I could protest that she never said anything about another box in the back seat, she just let out a sigh and shook her head. "Ok, Greg, where are the keys? I guess I'll have to get it my self."

I didn't have time to tell her the keys were in my hand when she started to "search" my pocket like I did hers. While standing directly in front of me, she reached around with both hands and felt my back pockets. I noticed the sly look on her face, and just assumed she was giving me the same treatment I gave her. She then walked behind my and repeated the routine to my front pockets, but with only one hand, her left. She patted my front left pocket, then reached over and tapped my right pocket, but not before running her hand lightly over the fly of my jeans. She then brought her hand back to the left side and slipped her hand into my pocket with her left hand, and then her right hand found it's way into my right side front pocket. Moving her finger tips inwards, both of her index fingers pressed against each side of my cock. She held her hands there a few seconds then asked. "Should I continue?"

I wasn't sure if she was just teasing in a very intense way, or was she really serious, but I was like a teenager in heat and my cock started to swell. I guess she could tell I was starting to get a hard-on and slowly moved her fingers up and down my cock as far as the pockets would allow. I felt her sort of pull me back into her while she spoke. "Well, I guess I can take that as a yes, correct?"

I think I muttered yes, but I felt like a statue and just held the box in my arms while she blatantly massaged my cock through my jeans until I had a raging hard-on. She then removed her hand from my crotch and I head her exhale loudly and then she simple said. "Ah, what now? I mean are you serious, and if you are, then yeah I'm game. So?"

I sat the box on the table and pulled her close and pressed my lips to hers, while I kneaded her nice tight buns through her jeans. Right then I didn't want to actually do anything, but I was so fucking turned on, I couldn't stop. Suddenly I remembered something that she said years ago that turned her on, and that was when a guy would nibble on her ear lobe and tongue her ear gently. Since I was beyond being rational, I figured I may as well bring her with me, and started at the knap of her neck and worked my way up to her left ear, the one she said was the most sensitive. It took all of about ten seconds of tonguing her ear before she hungrily pressed her lips to mine and plunged her darting tongue deep inside my mouth.

As I returned her passionate kisses, I slid a hand under her t-shirt and pushed her bra up and let her breasts fall free. As I took the nipple of her left breast between my thumb and forefinger, she tugged at the zipper of my jeans. Finally getting the zipper completely opened, she reached in and struggled to get my hardened cock from out of my jockeys. Frustrated, I quickly unsnapped the tab and let my jeans fall to the kitchen floor. Without me saying a work, Kathy knelt down and as I lifted each foot, she pulled me jeans from my legs.

I didn't know it at that moment, but my brother-in-law has a below normal size cock, about five inches she said, and although I am not built like a porn star, it does measure about nine inches. To me that was normal, at least at the gym I didn't appear to be any different then the guys I played racket ball with, but to Kathy it was the biggest cock she had ever seen. Of course, her husband's was the only one she saw before mine, so it wasn't all that big a deal.

"Oh my god, it's so fucking huge."

While she continued to slowly stroke my cock, I reached down and placed both hands on her head, hoping she would take the hint. Finally she leaned forward and ran her tongue over the head and lapped up the large drop of pre-cum that had developed. After savoring the clear liquid for a second or two, she opened her mouth and began slowly giving me the best blowjob I had ever had, up to that point in time that is.

She would roll her tongue over the swollen head as she bobbed her mouth up and down my swollen tool, bringing me closer and closer to filling her mouth with hot love juice. As I felt the explosion in my nuts rapidly approaching, I began rocking my hip back and forth, while my legs began to tremble. Now since my wife simply refuses to let me cum in her mouth, let alone swallow, I tried to let Kathy know I just about there. Finally I couldn't hold back anymore and moaned. "That's it Kathy I'm there, I am gonna cum. Oh here it is."

At that point I really thought she would be like her sister and pull her mouth off and jerk me to climax, but she started moaning and sucked even harder, while she massaged my swollen nuts. I never had that done to me before, and when she gave my nut sack her first gently squeeze, that was it. My cock started to spasm and I counted at least six violent spurts, and another four or five smaller ones before my eruption was over. Kathy continued to suck my slowly dying cock, and when she stood up I thought she was going to spit in the sink, but all she did was take a big breath and say. "Oh fuck Greg you must have shot a pint of cum. I had trouble swallowing it all."

That was the beginning of our secret affair that went on for almost a year before trouble appeared. One day she was talking with her closest friend Connie, who happened to be a horny as she was, and somehow mentioned that I was really hung. She didn't really mean to let it know that we had something going, and quickly tried to explain that she just happened to walk into an unlocked bathroom while I was draining the lizard.

I don't know if Connie actually believed her, but was a little more than just interested in seeing exactly what was living in my jockeys. Now don't get me wrong, it's not that I was trying to lay every one around but my wife, but she really was coming on hard one evening at a party Kathy and her husband John were hosting. Karen was fighting a bad case of the flu, and about ten o'clock or so she apologized but said she just had to go home and get in bed. Naturally I was also going to leave, but Karen insisted I stay and have a good time. No sense both of us missing out on the good time, she offered.

An hour or so later Connie and I were having just a nice conversation, nothing provocative, just friendly chat while we sipped our beers. Felling like I was going to explode, I placed my beer on the ledge on the deck, and excused myself. On the way inside I got sidetracked for a few minutes, and by the time I was making my way down the hall towards the john, I could see Connie a few steps in front of me. "Oh what the shit Connie, come on hurry up, I am about to bust."