To unlock this, you will need a touch screen device with Smartglass. When you boot up Smartglass, it should automatically change to be specific to Sesame Street TV. Click on Interactive Episodes, select any episode and click play. Once the episode is playing, click the camera at the bottom right hand corner of the screen. The achievement should unlock immediately. You do not need to quit back to the main menu to have this unlock, nor do you even have to have the pass for Season 2.
If you are having issues with the Smartglass functionality, you may need to create a new XBox LIVE account. The smartglass functionality is not available world wide. Even if you have access to Smartglass on your regional marketplace, you may have to create an American or British XBox LIVE account to get these achievements. See this thread to find out how to do that. After that, you will need to sign in that account on your smartglass device (it may involve resetting your phone to factory settings, so beware), sign into your console with the new account and with your main account on a second controller. Follow the instructions above and the achievement will unlock for both profiles.