After Simcess split up, Lars Boutrup joined the Slag Twins: Johnny Grauengaard (vocals) and Christian Springer (drums) and formed the group Sing-Sing. They made the album: Human Cannonball (1995) and their critically acclaimed cd The Black EP from September 1994, including the hit song Jennie, a song inspired by Marilyn Monroe.

Sing-Sing played a melodic rock style with an emphasis on fine vocals performed by all band members. They even had their own great cannon to promote their touring, but the audience couldn´t see the point! Sing-Sing finally disbanded in 1996.