Using a 10 inch long one quarter inch diameter plastic straw loaded with 7 inches of firm Mud, I work all of it into my urethra. I then follow by loading another 6 inches of firm Mud from the straw completely into my urethra. For good measure, I manage to work in another 2 inches. That totals 15 inches of Mud and since my urethra is only 8 or so inches long, I'm sure the entire volume is packed with Mud. The added weight from the Mud is obvious, I can also feel the entire length of my cock has the urethra bulging from the presence of the Mud.

When cleaning out the straw to use again, I found the traces of Mud quite tenacious and difficult to clear out from the straw, implying that the sounded Mud will equally adhere to the interior skin of my urethra. This Mud will be staying around for a while.