Eat rotten food
Mash turnip and sugar together
Get drunk
Have lots of hot water bottles and stuff then in your bed
Watch shock videos
Sir next to the sick person
Visit a sick person
Eat a lot of food
Sit in a freezer fro half an hour
ok but seriously, a combination of lots of salt water, a toothbrush up your mouth (it works better then fingers) and smelling shit that smells works well