“put the seat up” = put the toilet seat in the vertical (standing) position
Women use the bathroom with the seat down. So if a woman uses the bathroom, when she is finished the toilet seat will be “down” – resting horizontally, parallel to the floor.
So then when the guy goes in there, and he just has to urinate, he doesn’t want to piss on the seat. So he puts the seat up so that he has a wider margin for error.
Men here are taught – nay, admonished – to put the seat back down when they are finished using the toilet in such a manner (#1, I’m saying). If the man fails to put the seat back down… if he leaves the seat up… that pisses off some women.
in this case, “crack the whip” might be both literal and idiomatic.
The idiom is like this: in America, most married couples operate on the premise that the woman is always ultimately right and that when she wants something, she gets it. (don’t holler, ladies… you know it as well as I)
When she “cracks the whip”, it’s her sign, to the man, that that man is to service her in some fashion. If “crack the whip” is used, it implies that the man will go panting to her, like a dog, to obey her every command.
When I was in high school, a girl invited me over to her house one evening when the rest of her family was out. At some point I took a pee, and when I came back out, with the utmost urgency she told me make sure I’d put the toilet seat back down. Her mother was a widow, so the only people living in the house were the mother and three daughters. The girl knew from experience that if her mom found that toilet seat up, she would immediately catch hell for having a boy over on an unsupervised visit.