class Object
{
    Object(const Object&) = delete;
    Object(Object&&);
    Object& operator=(const Object&) = delete;
    Object& operator=(Object&&);
    [...]
};

std::vector<Object>   container;

container.reserve(42) // Reserve a lot in order to be sure it won't be a problem

container.emplace_back(1);
container.emplace_back(3);

auto it = container.end();

it--; // Last position.
it--; // Before last position.
container.emplace(it, 2);