Below is the South Park Studios description for the episode...
South Park: The Ring --- Original Air Date: 03.11.2009
Thinking it's his way into her heart and other body parts, Kenny takes his new girlfriend to a Jonas Brothers concert. His dream of taking their relationship to the next level is crushed when the Jonas Brothers give them purity rings.
Tags: Jonas Brothers, Kenny, girlfriend, Tammy Warner, concert, purity ring, Mr. Mouse, sex, Cartman, Butters, Stan, Kyle, B.J.
watch it at South Park Studios here.