1. A test you perform upon yourself to see if you really want to date the woman you're with or if you're just trying to have sex with her.
2. Putting on pornography and masturbating an hour before going on a date. Upon ejaculation, if you still feel like going on the date, you are really serious about having a relationship with the woman. If not, then you're just looking for sex and have saved yourself a ton of cash.
It is the street term for the psychoactive substance derived banana peels. It is smoked, inhaled, or injected for an intense high between LSD and DMT. Supposedly US Soldiers used to smoke "banrack" in Vietnam.
A banana is treated with a series of lighter fluid and ether for a span of a few days, then allowed to dry. Then you have banrack, and it is smoked. There are often several other methods, and other ways it is smoked similar to crack.