120 degrees fahrenheit is around what your hot water heater is probably set as. Run the tap all the way hot and see how long you can leave your hand in that and

120 degrees fahrenheit is around what your hot water heater is probably set as. Run the tap all the way hot and see how long you can leave your hand in that and then imagine putting your genitals in that for 45 minutes every day for three weeks and then repeating that every 4 months to avoid a gap in efficacy. That's just a terrible idea for practical contraception.