If you don’t feel like iterating, try
FBFriendModel.find({ id:333 }).remove( callback );
or
FBFriendModel.find({ id:333 }).remove().exec();
mongoose.model.find returns a Query, which has a remove function.
Update for Mongoose v5.5.3 – remove() is now deprecated. Use deleteOne(), deleteMany() or findOneAndDelete() instead.