It was during SHINee‘s performance at the 2012 KBS Music Festival on December 28. Poor Taemin. His pants apparently had had enough of the dancing and protested. The skinny jeans decided to rip down the middle and exposed his underwear while they were doing the squats that were part of the choreography. At least it was towards the end of their performance. Taemin handled it like a professional and finished the performance like a soccer player defending a free kick.
This was probably quite embarrassing for Taemin. Actually, if I were a member of SHINee there would be no end to the teasing. I bet it was horrifying for KBS. But, it was a glorious moment for SHINee fans.