Green’s Dictionary of Slang

abraham’s bosom n.

[punning on the biblical use meaning the ‘abode of the dead’, e.g. at Luke 16:22: ‘The beggar died, and was carried by the angels into Abraham’s bosom.’ In both SE and sl. senses the implication is of ‘lying on’]

[late 19C] the vagina.

In phrases

be in Abraham’s bosom (v.) (also take a turn in Abraham’s bosom)

to have sexual intercourse.