Okay kiddo, do you know what a salute is? It's a special way to greet someone in the military. Soldiers do it by putting their hand up to their forehead like this.
Now, do you know what a trap is? A trap is a type of electronic music that has a repeating beat and cool sounds. It's really popular with some people.
So, saluting trap is when someone in the military does a salute while listening to trap music. Some people might think it's cool to combine these two things together. But remember, it's important to always be respectful and follow the rules when greeting someone in the military, even if you're listening to music at the same time.