In the United States, your friends won't be solicited aggressively in the motel room. However, your boy is almost a man now.
There is nothing you can do to keep him from sexual exploring. The good example of you own life is all you can give him. Try to "protect" him, and he'll resent you -- and rightly so. He'll make mistakes. You may find out. Forgive him. Be proud that he's on his own now.