A cowboyish way to ask a woman to prepare for sex.
I told Marylou to get back in the camper and saddle her up!
When resting scrotum on top of another mans shaft
When Stephan saddled up old Roy and took the shaft for a ride
Saddle up the hay bed is a way of saying hit the hay but instead of falling asleep you're preparing to go to sleep.
Well fellas I'm gonna saddle up the hay bed.