From a delirious drunk pot head asking for water. The tube is actually the bottle that holds your drink, and in a car with no cup holders you will hold that tube in your crotch, hence the definition crotch tube
"were getting drunk using crotch tubes tonight bra"
"My crotch tube holds more rum than your crotch tube"
"My crotch tube holds more rum than your crotch tube"
by Dangerousdavis July 21, 2008