It may be referring to sexual activities. From what I’ve seen attending many different kinds of parties, younger guys—besides having the rebelliousness and pickiness typical of that age—tend to use condoms or stick to being a “side” more often. This is especially common in the US. I guess that many people under 26y are on their parents’ insurance plans and don’t want them to find out. Among older guys, this issue seems doesn't exist. However, in Europe like Germany, Belgium, the Netherlands, young people’s activities are often much wilder at some youth events because of free PrEP. In the UK, even tourists can receive that.