Sleep for 4-5 hours every weekday because you don't want the next day to begin so you put off sleep as long as possible, then sleep through the weekend.

Drugs

Training. Keep sleeping less than 4 hours / day one week or two in a row, or for a few months, or years... Then watch how the system just shuts down while wanting to be released from the flesh prison.

Another easy way is to do 2 or 3 days in a row without sleeping at all.

Being chronically ill and clinically depressed does the trick for me (though I've never slept for 24 hours straight, I wake up hungry after 12ish hours and go back to sleep after eating).