two lamps burning and no ship at sea

are your ears burning

Asked of somebody who was not present but was the topic of discussion.

beast with two backs

Two people united in sexual intercourse in the missionary position.

book burning

Any mass destruction, removal, or recalling of books, motion pictures, broadcasts, or electronic works as a form of censorship, especially motivated by religious or political objections to the material.

burning question

An important and pertinent question that urgently requires an answer.

carbon burning

The nucleosynthesis process, in stars of greater than 8 solar mass that have exhausted their helium supply, in which carbon is converted to neon, sodium, magnesium and other elements.

drop in the sea

A very small or insignificant amount; something of little importance.

ears are burning

Being the topic of discussion in another place; or sensing that this is happening.

eat for two

To be pregnant