Looking for a story: Boy, His GF and his Sister on a boat

[vveeekkeee]

Hi,

I read a story sometime back - A boy takes his girlfriend and his sister on a boat trip for a couple of days. Starts with skinny dipping, sun bathing, sister peeking over his brother and GF having sex and then including her.

Could not favorite or bookmark the story that time but would love to read it again.

Please help in finding back the story. Tried all possible tags and google search to search it.

Thanks,
Vveeekkeee