A funny wordplay referring to female audio jack. It is coined by Mehdi Sadaghdar, well known by his YouTube channel called ElectroBOOM, who usually shocks himself with electricity. In his video called 'Trying to Make a Wireless Lavalier Microphone', he used that expression to call the thing, which I have written about at the start of the description. (Yes, I learn British English)
Salesman: What would you like to buy?
Customer: I'd like to buy an audio janet.
Salesman: What?
Customer: I'm talking about a female audio jack.