OK, I had to look up SOUNDING, as I had no clue what it actually meant.
What is Sounding? The Kink Where You Stick a Rod Up Your Urethra
Also called “cock-stuffing,” “urethral sounding,” or sometimes “catheter fetish,” sounding falls under the larger umbrella of “medical play,” and involves inserting a sound (a long, thin rod, often made of surgical steel) into the urethral opening (the pee-hole) and down toward the bladder (the pee storer? Pee closet!). So, to clarify, the urethra is the canal that transports pee or semen out of the body, and “sounding” is sticking a tiny metal rod (or something else, if you're adventurous) into it.
OK, well that will be off during my game play.
I hope this helps others to know what it is...if you didn't know like me.
Regards.