When I (Dutch, 45m) was 18, I still was a virgin. A lot of my friends were too at the time. That year, 1995, we went on a vacation to one of the Dutch islands (Texel) and made a bet that the one(s) that would lose their virginity in those 2 weeks, would not have to pay for the camping where we were staying.
Of course, 8 guys in their late teens are super confident they all are going to win, but as we all know, a lot of that confidence is big talk.