Verbalized noun: 1) your friend, standing emotionally in front of you purposely taking the bug splats of unfriendliness.
2) The part of your friendship that is transparent enough to overlook your friends oversharing.
1) I normally wouldn't go to one of Tom's partys, he's such an ass; but with Alicia as friendshield it might be fun.
2) Jenny was telling me about her girlfriends yeast infection, now my friendshield's all dirty.
the situation arising from a desire to invite one friend to an event which results in a social obligation to invite a large number of additional friends to said event
Inviting Smiley Sue means you have to invite Laughing Lisa, which then leads to inviting Debbie Downer. And if you invite Debbie Downer, you need to invite Smelly Steve. And so on and so on....
Example: "I would love to invite you to my party, Smiley Sue, but doing so would inevitably lead to a friendalanche."