Promiscuity means having a lot of romantic or sexual relationships with different people.
Just like how you have different friends, some grown-ups have different people they like to kiss or cuddle with. Some people like to have just one special person they are romantic with, but others like to have fun with different people.
It's important to remember that as long as everyone involved is happy, safe, and respectful, it's okay to have different preferences in how we show affection to others. But grown-ups need to make sure they are always making healthy and responsible choices in their relationships, such as using protection if having sex and being honest and respectful with everyone involved.