For four years, the Equestria Girls have given us so many songs sung by the main characters. But only a few secondary characters ever have a solo or song of their own. That includes Flash Sentry, a male student (who almost every brony seems to hate because of him being a stuck up love interest). But I think a song that doesn't reflect on romance with him singing it himself could bring more development. 

Also recently in Season 7 (now that's it through), Vincent Tong (Flash Sentry's voice actor) has gotten the chance to sing songs on the series as different characters- Feather Bangs in "Hard To Say Anything" (singing "Battle for Sugar Belle) and Rumble in "Marks and Recreation" (singing "Blank Flanks Forever"). 

Plus, With the recent Equestria Girls webseries coming in a couple of weeks I would be surprised to see a song with Flash Sentry singing it. But the chances of that seem pretty slim so it wouldn't hurt to try. 

Don't care if it's by Daniel Ingram (who recently left the EqG to focus on the My Little Pony: Friendship Is Magic show). or any of those songwriters that wrote the songs for the summer shorts we had over the summer. Just make it something the represents the magic of friendship.