It's bad to pee on your bed.
Zach is half-awake in his bed around midnight after having had a large cup of tea before bed.
Zach wants to pee.
Zach gets up and goes to the bathroom to pee.
Zach pees in his bed before going back to sleep.
Zach feels relieved and goes back to bed where he sleeps soundly.
Zach sleeps poorly as his sheets are all wet with pee, and he has to wash them the next day.