"A deal's a deal.”

Before anyone responded, I interjected on instinct "Eh, a deal's a deal."

I stood up and pulled my shorts down in one swift motion before I lost my nerve. I hadn't drunk much at this stage, but I like to think I had enough of a buzz to justify my rash actions. My dick sprang into the air and I looked at Paige as I did this, her eyes were wide and her mouth was open. Then I sat back down, partially hiding my cock in the bubbly water, its head quite visible as it almost broke the surface.

"Holy shit. That looks massive." said Melissa, "how big is that? It's much larger than Andrew's." Andrew was Melissa's boyfriend, she was the only one of the group to have a boyfriend.

"7 inches." I said. I had never thought of my dick as particularly large, but I was happy to hear Melissa say otherwise. It made me feel superior to Andrew somehow. Andrew was in my year level at school. I never liked that guy, he thought too highly of himself, and it showed. He was a bully basically. Suddenly I wished it was Melissa who'd offered to give me a handjob, just to stick it to Andrew.

"Great, that's something I needed to know." said Paige. She sounded exasperated.

I slouched back and relaxed as Kara inched closer and reached for my cock. She started lightly caressing it and then slowly jerking it as she wrapped her hand more firmly around my tool. I stretched my legs out and put my feet up on the seat opposite, the space freed by Dawn's absence. This allowed me to rest my shoulders on the edge of the spa and float to the surface, my cock protruding completely from the water near the center of the spa.

Kara's hand moved up and down my shaft faster and faster. I closed my eyes and zoned out as the girls talked amongst themselves. I focused on the sensation in my dick as the buxom blonde to my left performed her promised handjob. Moments later her hand disappeared, then reappeared from a different direction. My eyes opened in a flash and I found Melissa now had her fingers wrapped around my tool. Suck on that Andrew I thought, your girlfriend is pleasuring my superior dick.

My eyes darted to Paige and then quickly back to Kara's massive tits. My sister seemed to have forgotten she was sitting in a spa with 3 other people and was staring intently at my dick while her hand seemed to be between her legs. This almost tipped me over the edge, but luckily Melissa released my dick right at that moment.

Kara's hand returned soon after and resumed her handjob. I stared at her tits which bounced lightly on the surface of the water as her arm jerked up and down, milking me. Then I started darting my eyes around trying to look at Paige without her knowing. I glanced at Amanda's tits, then Melissa's, then to my sister's water concealed crotch and back to Amanda's chest. Paige's arm was definitely moving slightly, she was covertly masturbating to her brother getting jerked off by her friend! Never in my wildest dreams had I imagined such a thing. It was a massive turn on however and after a couple more discrete glances I couldn't hold on anymore.

My cock erupted and I spewed cum everywhere. Thick gobs of it landed in the water, on my stomach and dribbled down Kara's hand. The girls all screamed in delight and reflexively jerked backwards, having not realized they'd all slowly lent forward to watch.

"That was interesting." said Amanda.

"That was hot!" amended Melissa.

I relaxed back into my seat, the cum washed off my body by the water. We all sat there in silence for the next 10 minutes or so watching my cum float around the spa, being pushed around by the air jets erupting from the surface. I noticed a clump float into Paige's side. I tried not to look, but the thought of my semen contacting my sister's skin was a massive turn on. I was quickly hard again. I secretly wanted another handjob. I secretly wanted my sister to administer it. But the girls had other ideas and started climbing out, apparently that was enough for the night. Kara grabbed her towel and wiped the cum on her hand into it. I hadn't realized that she had left her hand covered in cum, my dick jerked harder. I climbed out of the spa and put my shorts back on.

"Hehe. He's hard again already." said Amanda, pointing at my dick as I pulled my shorts up.

"What can I say? I'm surrounded by topless women, I'm only human." I replied.