I parked in the driveway, but didn't see anyone, so I thought they were probably in the back yard, maybe by the pool. The house belonged to Kate, one of my best friends. Her husband had been killed in a car accident three months earlier.

As she was on her own, I had told my son to help her out by weeding her gardens, mowing her lawn, and cleaning her pool. I told Kate to go ahead and use him for any other odd jobs that she needed done. I hadn't told her that I was paying him for his time, and made her think it was just a friendly gesture. He was only fifteen and couldn't get a summer job anyway, so this at least gave him pocket money. For me, it was a way of looking out for my friend as she readjusted her life.

My son, Derrick, is tall for his age, and had started filling out quite well. I could tell that he was going to be a handsome man, like his father. He had also been spending some time in our garage gym lately, lifting weights and working out on the exercise machine. I had seen him with his shirt off, sweaty from a workout, and realized that he had developed quite a set of chest and abdominal muscles.

As I walked into the backyard, I discovered that he had developed quite well in other areas. He and Kate were by the pool, although more correctly, she was in the pool, and he was sitting on the deck, with his legs in the water. Neither one of them had bathing suits on. His legs were spread, and her head was moving up and down between them.

I was a little shocked, and stood rooted to the spot. In a 'fight or flight' moment, I didn't know whether to say something, or to turn around and go back to the car. In the end, I kicked off my shoes, and moved onto the grass, quietly working my way to one side. Not really thinking about what I was doing, I got a better view of her working on my son. I was impressed by two things: her ability at sucking cock, and the size of the cock she was sucking.

Kate was working from the tip all the way to the root on each stroke, her nose ending up in his pubic hair, pausing for a moment each time she bottomed out. I could even see her tongue coming out to lave his balls when she hit bottom. At the other end, her teeth were nibbling gently on his head, and her tongue was whipping back and forth on the sensitive spot under the crown.

The cock she was sucking was impressive for anyone, and especially for a fifteen year old boy. He was larger than my husband, both in length and girth. I was surprised, and at the same time feeling twinges of both jealousy, and arousal. 'What are you doing, that's your son?' flashed through my mind. I could hear Derrick moaning softly every time that Kate hit bottom.

Involuntarily, a hand started playing with one of my nipples, which had both grown hard at the sight in front of me. I noticed other things about the two of them, like his left hand in her hair, not pulling her in, but just moving softly over her head. I also noticed the size of her breasts, as they oscillated with her movements, her nipples appearing and reappearing at the waterline.

After a minute, Derrick's right hand came up to Kate's head, and he went from moaning to calling her name in a low, guttural voice. I judged that he was about to come, and an instant later he pulled her head tightly into his groin. I could see his muscles convulsing as he came, and he bent into a curve over the top of her head, grunting with each blast. Amazingly, she didn't struggle as he held her, and I was impressed by her breath control, in addition to her other talent. Given his size, and the way her face was held to his crotch, I thought that he must be coming straight down her throat.

After a moment, he relaxed his tight grip on her head, and she pulled back about halfway, sucking in a breath through her nose. I could see her mouth still working, and thought that she must be catching the final drops on her tongue, and washing the head clean. He let out a long moaning sigh, and said, "Damn, I can't believe how good that feels, and how good you are at it."

As Kate finally pulled her lips back off his cock, and ran her tongue around them to get the final taste, I spoke up, "Yes, it was rather impressive." Two sets of eyes swung to look at me, panic in my son's, but strangely not much emotion in Kate's.

"Mom!" cried Derrick in a strangled voice; realizing that he was naked in front of his mother, he madly scrambled for his discarded clothes. Kate, on the other hand looked at me coolly and merely said, "Hello Anne."

As Derrick struggled into his clothes, trying to tuck his still rampant erection into his shorts, I glared at him and said, "Wait in the car. I'll deal with you later. I want to have words with Kate." He ran from the yard, carrying his shirt and sneakers, not waiting to finish dressing, simply wanting to escape the wrath of his mother.

I walked over to the edge of the pool, and stared down at Kate, "So, how long have you been fucking my son?"

She looked up from the water, and asked, "Can you at least sit down so we can talk? The sun is in my eyes at this angle when I look up."

Still fuming, I realized that she had a point, so I sat down to one side of her, and let my feet dangle in the water. I glared at her again. "So, how long?"

"Well, technically I haven't been fucking your son. I've blown him a few times, and oh yeah, I did give him what amounted to be a handjob once." She chuckled a bit and went on, "He didn't have much control the first time I put my hands on his dick."

"You don't seem to be very worried about this. He's fifteen! You could go to jail."

"Anne, have you looked at your son lately? He's gorgeous. When school starts up again, he's going to have girls drooling on him, and throwing their panties at him. The first time he took his shirt off, I dropped the glass of iced tea I was bringing him. I couldn't help myself. Having ... that ... so close was just too much to take. And the first time I saw his cock..."

"Enough. I don't need you to talk about his cock. I'm his mother for God's sake!"

"And as his mother, you should be thankful that someone more experienced is guiding him through the first sexual experiences, instead of some ditzy blonde with big tits, who'll end up getting knocked up, or who'll give him a dose like the other three guys she fucked that day."

"Guiding him through ... what a load of crap! Where did you come up with that one? Some women's magazine?"

Kate burst out laughing, and shrugged her shoulders, which did interesting things with her breasts as they floated in the pool. "Well, it was worth a shot." She moved closer to me, and put a hand on my knee. "Look Anne, I'm sorry if I hurt you. I told Derrick not to say anything, because I was afraid you'd feel this way. Since Ken died, I've had no one other than my vibrator, and I've been going through a lot of batteries. When I saw Derrick with his shirt off, I just kind of snapped, and my pussy got so wet I couldn't help it. If I were a guy, you would have said that I was thinking with the little head, and not the big one. I guess I was just thinking with my clit."