Thanks for actually trying this! I tried to get hold of syrup of ipecac, which seems to reliably cause vomiting, but it's hard to get in US pharmacies, and Amazon doesn't sell it (except homeopathically). Did your friends say that mustard water works better than syrup of ipecac?
Thus spake Eliezer:
It seems that many here might have outlandish ideas for ways of improving our lives. For instance, a recent post advocated installing really bright lights as a way to boost alertness and productivity. We should not adopt such hacks into our dogma until we're pretty sure they work; however, one way of knowing whether a crazy idea works is to try implementing it, and you may have more ideas than you're planning to implement.
So: please post all such lifehack ideas! Even if you haven't tried them, even if they seem unlikely to work. Post them separately, unless some other way would be more appropriate. If you've tried some idea and it hasn't worked, it would be useful to post that too.