Joe Jonas: When You Gotta Go, You Gotta Go ...

Joe Jonas learned there's a not-so-glamorous side of rock 'n' roll too when he was forced to use a porta-potty just like the rest of the crowd ... at his own concert.

Joe's band, DNCE, performed in Miami Sunday at Model Volleyball, which is exactly what it sounds like. Just a guess, but ... getting to watch hot athletic chicks in bikinis frolic in the sand all day should take the sting out of the nasty bathroom experiences.