THE BACKSTREET BOYS did an interview with Billboard for the 20th anniversary of their first album. And they also told a story about their fourth album . . . because it turns out a bass line on their song "The Call" is actually one of them PASSING GAS.
While HOWIE DOROUGH was recording his harmony, he got really into it and LET ONE SLIP. Then instead of re-doing the vocals, their producer decided to tweak the audio . . . made it sound like a BASS note . . . and left it in the song.
AJ MCLEAN talked about it, and said Howie did it on beat, and ON PITCH. So, his butt basically became an "instrument," and they decided to leave it in.