social buffer
noun. A person who acts as a social cushion against awkward conversations and social situations for the sake of a friend.
"Please come with me to Anthony's wedding, its going to be so awkward! I don't know anyone there but him- you have to be my social buffer!"
"Casey keeps asking me to come to Thanksgiving at her place this year but I hate being her social buffer, I always end up having to make conversation with her drunk uncle."
"Casey keeps asking me to come to Thanksgiving at her place this year but I hate being her social buffer, I always end up having to make conversation with her drunk uncle."