Me and an ex were on vacation with both our families. We ended up taking a ferry somewhere and me and my ex kept trying to sneak away from our families for some fun but my ex’s older sister kept following us around. We eventually decided to give up and just sit in some random seats until the ferry ride was over because we couldn’t shake her sister. Next thing I know my ex throws a blanket over me and her (not her sister) which didn’t seem strange at the time because it was a little cold on the ferry. But then I felt my ex’s hands go down my pants and pull my cock out under the blanket. I was so shy with her sister right there that I kept trying to act cool but from her hand movements under the blanket and my face and noises it was obvious. All of a sudden my ex’s sister goes “I know what you’re doing under there” which was frightening and hot but my ex didn’t stop. I ended up cumming in front of them both under the blanket. It was a wild experience haha