Used in conjunction with a joose-bag, the joose nozzles are used singularly as a tip of which is inserted into the rectum. This is to facilitate the process of receiving an alcohol enema. This is commonly known as "getting joosed," due to the use of the Joose brand flavored and caffeinated alcohol beverage as the alcohol of choice.
The joose nozzle can be of varying size, diameter, and length, depending on the experience of the recipient.
Pictures of a joose nozzle can be found here (section 6):
Hey Leeroy! Make sure you sanitize them joose nozzles before you stick any of em in your ass and get joosed!