Want a fever in one hour or even less? The best thing to do is forget about getting an actual fever (so all those people saying that you should have a cold shower and then site outside in your underwear are idiots.
Instead, you should focus on replicating the symptoms of a fever, namely:
- raised temperature
- shivers
- sweating
The shivers you can easily fake, and a damp cloth will take care of recreating a sweaty brow, but the temperature thing will depend on one key factor:
How is your temperature being taken?
If it's orally, then you'll need to take a sip of tea or something else that is 39 degrees celsius/102.2 fahrenheit.
If your parents use an ear-thermomeneter to take your temperature, then you can try placing your ear right in front of a warm lamp . Just be REALLY careful not to burn yourself as that would be bad.
If you are being checked with a "rectal" thermometer by your parents, then you probably have bigger problems than worrying about faking a fever.
