I am tired and need twenty winks.
twenty winks
idiomA very short sleep, half as long as forty winks.
Origin
disputed originModeled after forty winks, from the humorous notion that if a short nap is forty winks then a very short nap is twenty winks (half that amount).
The long drive made me sleepy, so I pulled over to take twenty winks before continuing.
Exhausted from the long journey, the traveler found a quiet corner in the station to steal twenty winks before the final train arrived.