By Ayeesha Walsh Christina Applegate has confessed that she and a friend donated hundreds of dollars to a charity telethon while high on mushrooms. The Dead To Me star opened up to Dax Shepherd on his Armchair Expert podcast about how she tried mushrooms for “the first and last time” when she was 16. She then regaled him with the story of how she and her friend called up to donate a stack of cash to Comic Relief using her dad’s credit card. She explained: “My friend Mandy and I, we took some mushrooms, I think I was 16, at her house and we starting watching Comic Relief. This is how long ago i…