For the best torture ever, simply administer one Lasix pill. 40 mg ought to do it. But you have to give your MC this pill before:
A) a major agent requested revision is due
B) housecleaning for guests
C) packing for vacation
D) all of the above
Then sit back and watch as your MC is glued to the toilet for the next 27 consecutive minutes and:
A) her legs fall asleep for sitting so long
B) other characters gather and laugh outside the bathroom door
C) these same characters pin signs to the bathroom door that read "OUT OF ORDER" or "Out of Commission for the next 24 hours. Hope you can hold it." These signs must also include illustrations of toilets overflowing.
D) these hilarious characters (who will soon be grounded) slip items under the bathroom door while laughing.
These items consisit of:
1. pen and paper (might as well work, right?)
Have the husband stand outside the door and make comments such as:
A) "Bet you feel ten pounds lighter!"
B) "Better flush before it overflows."
C) "I think you just made a new world record!"
After 27 minutes have the MC emerge from the bathroom, shaken and numb, only to race back in the bathoom five minutes later. Every time the MC tries to get comfortable and relax, have that Lasix pill kick into high-gear sending them to the toilet, yet again.
Repeat this for the next 24 hours.
If your MC can emerge from this as a person who:
A) can tolerate harrassment
B) has the bladder the size of a rhinocerous
C) can laugh at themselves
then you've successfully tortured your character and refined them. They are now ready for anything that comes their way.
warning: do not attempt this on living people. ever. they will be scarred for life.