Wiktionary
sleep on
vb. 1 (&lit sleep on English) 2 (context idiomatic English) To postpone a decision at least overnight.
Usage examples of "sleep on".
Odd to sleep on a bare floor, too -- not that it mattered with low gravity.
The torch was guttering and filling the cave with smoke, so Yaqui extinguished the light In the darkness there was a rustling of straw and sundry groans and yawns as the prisoners lay down to sleep on the pallets.