After a while she started squirming in her seat and looked hot and flustered. I asked if she wanted me to stop and she said that she’d kill me if I did. I took this as an obvious sign to be bolder and gently pushed a finger inside her. She nearly jumped off our seat, which made me laugh. “That tickles,” she said and so in went two fingers much to her delight. Meanwhile, Jo, bless her, kept up a steady pumping action on my dick and I felt that familiar sensation just before I cum starting to arrive. I told her that if she kept that up I would cum there and then. Jo looked at me and boldly told me to wait while she got some tissues. She reached over and broke one piece of tissue off a roll and said, “OK then cum for me.”

I was honestly taken aback at her newfound boldness and was for the first time speechless. Could my lovely but shy sister-in-law be going to make me cum? She pulled my shorts to one side just as another boat appeared and pulled my dick out of its hiding place. She held the tissue in front of my dick and started rubbing faster and faster. I told her that the boat was coming and she just replied that it was not the only thing that was going to cum. That familiar sensation was rising in my balls and Jo was transfixed looking at the end of my dick. As the other boat passed us I waved with my spare hand a Jo stopped momentarily but squeezed my dick slightly harder which was enough to force me to cum! I started spewing blob after blob of cum into her tissue lined hand and she just kept looking intently at it pumping out my hot sticky cum again and again. The other boaters had no idea what we were up to!

Now, I have always produced a good quantity of cum; I guess it’s the size of my balls or just how I’m designed. Jo couldn’t believe how much cum I had produced and kept remarking on the amount. Once I had finished she carefully wrapped the tissue up but spilt a little on her hands and when I saw that I asked if she had ever tasted another man’s cum. She went really bright red but licked some off her finger and said that it tasted the same as Steve’s. She then got another piece of tissue and wiped my dick off. I did ask her to clean it with her mouth but Jo just tutted and went to throw the tissues away. I was now feeling a little bolder and asked if I could make her cum too. She smiled broadly and said that that was her general idea. I shoved my hand down her shorts only to find no bikini bottoms! She had removed them when she went to throw the tissues away. My fingers went swiftly to work on her