when two Sundays come together

as they come

As it is possible to be.

band together

to unite, to come together

bang some heads together

Attempt to get results from a previously ineffectual or argumentative group, typically by coercion or force.

beast with two backs

Two people united in sexual intercourse in the missionary position.

birds of a feather flock together

People of similar character, background or taste tend to congregate or associate with one another; it is easier to establish friendships with people that one has a lot in common with.

blow to kingdom come

To totally destroy (something); to annihilate or wipe out (something).

bring together

To cause people to do something together; to bring about togetherness.

Christmas come early

Something very delightful or fortunate that is happening or has happened, especially earlier than expected.